KR100971188B1 - Hi-attenuation vulcanized rubber and a elastomeric bearing using thereof - Google Patents

Abstract

PURPOSE: A rubber composition and an elastic support using the same are provided to obtain excellent tensile strength and stability by adding carbon fiber powder, a natural rubber, a butyl rubber, barium lactate, calcium carbonate, carbon black, and an additive. CONSTITUTION: A rubber composition having excellent stability comprises 10-23 weight% of a natural rubber, 19-21 weight% of a butyl rubber, 8-10 weight% of barium lactate, 33-35 weight% of calcium carbonate, 10-12 weight% of carbon black, 4-7 weight% of carbon fiber powder, and 3-5% of an additive. The additive 35-45 weight% of a softener, 35-38 weight% of a dispersing agent, 9-12 weight% of zinc oxide, 5-6 weight% of magnesium oxide, 3-4 weight% of antioxidant, 0.5-1.5 weight% of a promoter, and 2.5-3.5 weight% of sulfur. An elastic support using the rubber composition includes an elastic pad(40), a lower plate(30), and an upper plate(20).

Description

High-damping rubber composition and elastic support using the same

The present invention relates to a high damping rubber composition and an elastic bearing using the same, and more particularly, to a rubber composition having improved damping rate as a rubber composition used for an elastic bearing for a bridge and an elastic bearing manufactured using the rubber composition.

In general, buildings, bridges, and the like are rapidly being used to absorb vibration energy, that is, dust, dust, and seismic isolators. For example, the elastic support apparatus which laminated | stacked the rubber composition and the hard board alternately is used for the support stand of a bridge, the base seismic isolation of a building, etc.

By arranging the hard plates at equal intervals inside the rubber composition, the device is very hard in the vertical direction and smooth in the horizontal direction, that is, the shear stiffness is reduced, so that the natural vibration period of the building or bridge is shifted from the vibration period of the earthquake. By acting to release, the acceleration that a building receives from an earthquake is very small. The rubber composition used for such a use requires high attenuation which attenuates vibration energy by replacing vibration with heat.

To this end, according to the prior art, a technique for forming a rubber composition to have a high attenuation used as an elastic pad has been disclosed, but the rubber composition for elastic support according to the prior art has a problem that the damping property is lowered. That is, a rubber composition comprising a combination of synthetic rubber, natural rubber, filler, oil, accelerator, lubricating agent, softener, and the like has been proposed, but the damping rate of these rubber products is about 14% or less, and thus has not sufficiently high damping function. In addition, it was difficult to reduce the modulus of elasticity and at the same time to achieve a high attenuation and high fracture strength in a balanced manner.

The present invention has been made to solve the problems of the prior art as described above, the technical problem of the present invention is to provide a rubber composition excellent in tensile strength and elongation while high damping rate.

Another technical problem of the present invention is to provide an elastic bearing made of a rubber composition having high damping properties.

Another technical problem of the present invention is to provide a means that can prevent the phenomenon that the elastic pad edge of the elastic support made of a rubber composition having a high attenuation peeled from the upper and lower plates.

In order to solve the above technical problem, the present invention,

As a high damping rubber composition,

10-23 weight percent natural rubber;

19-21 wt% butyl rubber;

8-10 weight percent barium lactate;

33-35 weight percent calcium carbonate;

10-12 weight percent carbon black;

4-7 wt% carbon fiber powder; And

It provides a high-damping rubber composition comprising 3 to 5% by weight of an additive.

At this time, the additive,

35-45 weight percent softener;

35-38 weight percent dispersant;

9-12 weight percent zinc oxide;

5-6% magnesium oxide;

3-4 weight percent antioxidant;

0.5-1.5% by weight of accelerator; And

And 2.5 to 3.5 wt% sulfur.

On the other hand, the lower plate;

Upper plate; And

In the state where a plurality of reinforcing plates are disposed at equal intervals between the upper and lower plates, the upper and lower plates are made of an elastic pad that is vulcanized and bonded to each other,

The elastic pad is provided with a high elastic rubber composition according to claim 4, characterized in that the elastic support.

At this time, the upper and lower edges of the elastic pad is characterized in that the curved surface concave inwardly or inwardly formed.

On the other hand, the coating grooves of a predetermined depth are formed in regions except for the corners of the upper and lower plates, respectively.

Each of the coating grooves may be coated by inserting an extension portion integrated with the upper and lower portions of the elastic pad, respectively.

In addition, the upper and lower edge regions of the elastic pad including the coating groove and the extension part may be inclined outwardly or curved inwardly.

The high damping rubber composition according to the present invention and the elastic support using the same are natural rubber, butyl rubber, barium lactate, calcium carbonate, carbon black and additives, and carbon fiber powder is added, so that the toughness and elongation are good, but the damping property is good. Excellent rubber compositions are provided.

In addition, the elastic support having a high attenuation characteristics may be provided by configuring the elastic pad of the elastic support with a rubber composition having excellent damping properties.

In addition, by forming an inclined surface or a curved surface at the edge of the elastic pad, it is possible to prevent the edge of the elastic pad from lifting from the upper and lower plates.

1 is a cross-sectional view showing an elastic support according to a first embodiment of the present invention.
Figure 2a, 2b is a cross-sectional view showing a second preferred embodiment of the present invention.
3 is a perspective view showing a third preferred embodiment according to the present invention.
4 is a cross-sectional view showing the elastic support shown in FIG.
Figure 5a, 5b is a graph showing the results of the basic performance evaluation test of the elastic bearing according to a preferred embodiment of the present invention

When described in detail with reference to the accompanying drawings a preferred embodiment of the present invention having such features as follows.

Hereinafter, the present invention is applied to an integrated elastic support manufactured by combining the elastic pad and the upper and lower plates integrally. Therefore, the present embodiment will be described based on the integrated elastic bearing.

1 is a cross-sectional view showing an elastic support according to a first preferred embodiment of the present invention, Figures 2a, 2b is a cross-sectional view showing a second preferred embodiment of the present invention, Figure 3 is 4 is a cross-sectional view showing a third preferred embodiment, Figure 4 is a cross-sectional view showing a fourth preferred embodiment of the present invention.

The high damping rubber composition according to the present invention comprises 10 to 23% by weight of natural rubber, 19 to 21% by weight of butyl rubber, 8 to 10% by weight of barium lactate, 33 to 35% by weight of calcium carbonate, 10 12 weight% carbon black, 4-7 weight% carbon fiber powder, and 3-5 weight% additives.

Natural rubber is an unvulcanized rubber used for the preparation of the present composition. Such natural rubber (NR) and isoprene rubber (IR) can be used, and both can also be used together. When the amount of the natural rubber (NR) or isoprene rubber (IR) is 10 wt% or less, the tensile strength is lowered, and when the amount is 23 wt% or more, the elasticity is increased due to the repulsive stiffness. Can be. Therefore, preferably 17% by weight is added.

On the other hand, butadiene rubber (BR), styrene butadiene copolymer rubber (SBR), acrylonitrile butadiene copolymer rubber (NBR), butyl rubber as unvulcanized rubber which can be blended in addition to natural rubber (NR) or isoprene rubber (IR). Various unvulcanized rubbers, such as (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR, etc.), and chloroprene rubber (CR), are mentioned, It is not limited to any one component.

Butyl rubber has the lowest repulsive elasticity among various rubbers in a form in which the methyl group surrounds the main chain and makes the main chain difficult to rotate due to its molecular structure. Therefore, a high damping rubber that must dampen the impact plays an essential role, and also has properties of durability, ozone resistance, and aging resistance. In the case of such butyl rubber, the damping rate is lowered at 19 wt% or less, and at 21 wt% or more, not only the tensile strength is lowered, but also the hardness is increased, resulting in poor molding stability. Therefore, 20% by weight is most preferred.

Barium lactate is used as a filler. When added to 8 wt% or less, the damping rate is lowered. If it is 10 wt% or more, tensile strength is decreased, hardness is increased, and molding stability is low. Therefore, it is most preferable to add 9 wt%. Do.

In addition, calcium carbonate is used as a reinforcing agent, and when added below 33% by weight, the damping rate is lowered, and when added by 35% by weight or more, the tensile force is lowered, and the hardness is increased, resulting in poor molding stability. Therefore, it is preferable that 34% by weight is added.

If the carbon black is added at 10 wt% or less, the damping rate is lowered. If the carbon black is added at 12 wt%, the tensile strength is lowered and the hardness is increased, resulting in poor molding stability. Therefore, it is preferable to add 11 weight%.

In addition, the carbon fiber powder is to increase the damping rate of the rubber together with the butyl rubber, and the rigidity of the rubber composition is improved by mixing the nanoparticle form or the fine carbon fiber powder. That is, when the fine carbon fiber powder particles are uniformly infiltrated and mixed between the main chains of the rubber composition, the stiffness of the rubber composition itself may be improved since the movement of the main chain of natural rubber is reduced. In addition, since the carbon fiber powder particles control the movement such as rotation of the main chain between the main chain of the rubber, the damping property can be improved. When the carbon fiber powder is added at 3 wt% or less, the damping rate is lowered, and when 7 wt% or more is added, the tensile strength is lowered, as well as the hardness is increased, resulting in poor molding safety. Therefore, preferably 5% by weight is added.

On the other hand, the additives include 35-45 wt% softener, 35-38 wt% dispersant, 9-12 wt% zinc oxide, 5-6 wt% magnesium oxide, and 3-4 wt% antioxidant And 0.5-1.5% by weight of accelerator and 2.5-3.5% by weight of sulfur.

When the sulfur is added in an amount of 2.5 wt% or less, the room temperature durability may be lowered, and when added in an amount of 3.5 wt% or more, the heat resistance may be lowered.

In addition, the accelerator (vulcanization accelerator or vulcanizing agent) improves the crosslinking speed of the vulcanized rubber, and when the compound is undermixed, no effective vulcanization system is formed, so that the polysulfur bond cannot be achieved.

Antioxidants are used to improve the heat, flex and oxidation resistance of rubber.

In addition, dispersants, zinc oxide, and magnesium oxide are used to improve the dynamic properties and processability of rubber and to improve heat resistance. When such a dispersant, zinc oxide, magnesium oxide, etc. are under-incorporated, the activation of the vulcanization rate is weakened, and in the case of over-mixing, the vulcanization rate is increased, so that the scorch is generated and the properties of the rubber are weakened.

Therefore, the additive is preferably added 4% by weight.

Examples according to the respective mixing ratio of the rubber composition as described above are shown in Table 1 below.

Component / Results Example 1 Example 2 Example 3 Natural rubber 10 17 23 Butyl rubber 21 20 19 Barium lactic acid 10 9 8 Calcium carbonate 35 35 33 Carbon black 12 11 10 Carbon Fiber Powder 7 5 4 additive 5 4 3

In addition, the results of various tests of the high damping rubber manufactured according to each of these examples are shown in Table 2 below.

Test Items
unit Example 1
Result Example 2
Result Example 3
Result
Test Methods Static Shear Modulus MPa 0.7 1.04 0.65 KS M 6617: 2001 The tensile strength MPa 9 13.8 20 KS M 6518: 2006 Elongation % 620 700 530 KS M 6518: 2006 Hardness (Hs) - 45 63 52 KS M 6518: 2006 Adhesive strength kN / m 13 18.7 15.4 KS M 6518: 2006 Aging test ((70 ± 1) ℃, 72h) KS M 6518: 2006 -25% elongation change rate % 14.1 17.1 16.0 KS M 6617: 2001 Elongation rate % -2.3 -5.6 -4.2 KS M 6518: 2006 Compressive permanent shrinkage ((70 ± 1) ℃, 24h)
%
30
38
25 KS M 6518: 2006 Ozone crack test ((50 ± 5) pphm, (40 ± 2) ℃, 20% elongation, 96h) -
Cracking
No crack
No crack
KS M 6518: 2006 Immersion test ((55 ℃ ± 1) ℃, 72h, distilled water) - - - KS M 6518: 2006 Weight change rate % 0.5 0.9 0.63 KS M 6518: 2006 Impact embrittlement limit temperature (-40 ℃) clear clear clear KS M 6676: 2008 Attenuation rate % 16 17.92 15 KS M 6518: 2006

According to the test results, the higher the content of natural rubber, the higher the tensile strength but the smaller the elongation. In addition, cracks appear in ozone, which is inappropriate.

In addition, as the content of the carbon fiber powder increased, the damping rate was decreased, and when 7 wt% or more was added, instability appeared in forming the product, and the result was broken during the damping rate test. Therefore, when the 4-7% by weight, preferably 5% by weight is added, the attenuation rate is high.

 As a result of these tests, the preferred blending ratio of each component constituting the high damping rubber composition is 17% by weight of natural rubber, 20% by weight of butyl rubber, 9% by weight of barium lactate, 34% by weight of calcium carbonate, 11% by weight of carbon black, and carbon fiber 5% by weight of powder and 4% by weight of additives. In addition, the tensile strength of the high damping rubber composed of such a high damping rubber composition is 13.8 MPa, the elongation is 700%, and the damping is 17.92%.

Such a high damping rubber composition satisfies the specifications required by the contractor.

High attenuation having the characteristics as described above, that is, the elastic support 10 to which the elastic pad 40 manufactured using the non-elastic rubber composition is applied as follows. Hereinafter will be described based on the vulcanized integrated elastic support. However, the present invention is not limited thereto, and of course, it can be used for all kinds of elastic bearings.

As shown in FIG. 1, the elastic support 10 made of the high damping rubber composition according to the present invention has a lower plate 30, an upper plate 20, and a plurality of reinforcing plates 42 therein at equal intervals. It is made of an elastic pad 40 is vulcanized and coupled to the upper and lower plates 20 and 30 between the upper and lower plates 20 and 30 in a disposed state. At this time, the elastic pad 40 is made of a high-damping rubber composition according to the present invention described above.

 That is, the lower plate 30 is seated inside the lower mold (not shown), and the rubber plate and the reinforcing plate 42 made of the above-described high-damping rubber composition are alternately stacked, and the upper plate 20 is disposed on the upper plate. After mounting the upper mold and the lower mold, while pressing the contents of the lower mold inside at a high temperature, high pressure, the rubber plate is vulcanized by the upper and lower plates (20, 30) and the reinforcing plate (42) firmly The elastic pad 40 is formed while being bonded, and as a result, the elastic support 10 having the structure as shown in FIG. 1 is manufactured.

As such, the elastic support 10 made of the high damping rubber composition of the elastic pad 40 can greatly improve the physical properties of the rubber (material) such as damping rate, tensile strength, and elongation rate, thereby limiting the elastic support 10. It is possible to improve the shear failure characteristics.

As a basic performance evaluation test of the elastic support 10, the horizontal performance test and the compression performance test were carried out.

The horizontal performance test was performed under the conditions of vertical load: 360.0 kN, vertical speed: 500.0 kN / min, rubber thickness: 24 mm, horizontal strain rate: 100.0%, horizontal speed: 2880.0 mm / min, and the number of repetitions: 6 times.

Compression performance test was performed with vertical load: 550.0 kN, vertical speed 500.0 kN / min, number of repetitions: three times, upper limit load: 550.0 kN, lower limit load: 90.0 kN, number of samples: two.

As a result, the average effective stiffness from 1 to 5 times was 2922.655 (kN / m) and the average equivalent damping ratio was 18.5727 (%), as shown in Table 3 and FIGS. 5A and 5B. The compression spring coefficient was 576059.0 (kN / m) and the compressive strain amount was 0.000469 (m).

Test Items
unit
Result Compression Spring Factor kN / m 576069 Equivalent Stiffness kN / m 2923 Equivalent decay rate % 18.6

As shown in Table 3, the basic performance evaluation test of the elastic bearing with the elastic pad 40 made of the high damping rubber composition according to the present invention was found to have a high damping rate, compression spring coefficient, and equivalent stiffness.

On the other hand, the compression fatigue test, compression and shear fatigue test of the elastic bearing 10 according to the present invention, the temperature dependency test as a safety performance evaluation, the cycle dependency test as a safety performance evaluation, the surface pressure dependency test as a safety performance evaluation.

The result is as follows.

Compression Fatigue Test
Test Items
unit
Early
500,000 times
1 million times
1.5 million times
2 million times Equivalent Stiffness kN / m 2193.8 2459.3 2419.4 2415.8 2393.5 Equivalent decay rate % 19.42 18.17 18.37 18.06 17.98 EDC Area kN.m 3.0622 3.2024 3.1809 301285 3.0890 Appearance (breakage failure-crack) - clear clear clear clear clear Compression Spring Factor kV 7,351,111 6,872,916 4,867,647 3,595,652 6,277,358

Compression and Shear Fatigue Test
Test Items
unit
Early
1,000
2,000 times
3,000 times
4,000 times
5,000 Equivalent Stiffness kN / m 2193.8 2433.1 2631.2 2707.4 2702.9 2724.9 Equivalent decay rate % 19.42 16.08 15.41 15.05 15.13 14.57 EDC Area kN.m 3.0622 2.8053 2.9044 2.9183 2.9322 2.8462 Appearance (breakage failure-crack) - clear clear clear clear clear clear Compression Spring Factor kV 6,751,020 4,676,056 4,588,888 5,010,606 5,252,381 3,953,571

Safety performance evaluation (temperature dependency test)
Test Items
unit
-10 ℃
0 ℃
10 ℃
23 ℃
40 ℃ Equivalent Stiffness kN / m 2693.5 2429.9 2271.0 2139.6 2040.7 Equivalent decay rate % 19.55 18.42 17.62 16.74 16.63 EDC Area kN.m 11.608 9.8666 8.8286 7.8968 7.4923 Appearance (breakage failure-crack) - clear clear clear clear clear

Safety performance evaluation (cycle dependency test)
Test Items
unit
0.33 Hz
0.5 Hz
1 Hz
1.25 Hz Equivalent Stiffness kN / m 2988.7 3035.9 3071.8 3133.4 Equivalent decay rate % 16.84 18.01 19.73 20.01 EDC Area kN.m 1.7638 1.9126 2.1258 2.1962 Appearance (breakage failure-crack) - clear clear clear clear

Safety performance evaluation (surface pressure dependency test)
Test Items
unit
3.0 N / mm2
6.0 N / mm2
9.0 N / mm2
12.0 N / mm2 Equivalent Stiffness kN / m 2105.7 2315.9 2458.3 2615.0 Equivalent decay rate % 16.52 17.16 17.54 17.82 EDC Area kN.m 7.6806 8.7705 - 10.2796 Appearance (breakage failure-crack) - clear clear clear clear

The conditions of such test are as follows.

* Compression performance test-Vertical load 550 kN, Test load 385-715kN (550 ± 30%), Vertical repeat cycle: 0.1Hz, Vertical repeat count: 3 Cycle

* Compression and shear test-Vertical load: 6MPa, Horizontal displacement: ± 24mm, Horizontal repetition cycle: 0.5Hz, Horizontal repetition number: 5 Cycle

* Compression Fatigue Test-Vertical Load: 5.2-12.0 MPa, Horizontal Displacement: ± 16.8mm, Vertical Repeat Cycle: 2Hz, Vertical Repeat Count: 2,000,000 Cycle

* Compression and Shear Fatigue Test-12MPa, Horizontal Displacement: ± 16.8mm, Horizontal Repeat Cycle: 0.0056Hz, Horizontal Repeat Count: 5,000 Cycle

* Temperature dependence test-Vertical load: 6MPa, Horizontal displacement: ± 42mm, Horizontal repetition cycle: 0.5Hz, Horizontal repetition number: 4 Cycle

 * Cycle dependency test-Vertical load: 6MPa, Horizontal displacement: ± 16.8mm, Horizontal repetition number: 5 Cycle

* Surface pressure dependency test-Horizontal displacement: ± 42mm, Horizontal repetition cycle: 0.5Hz, Horizontal repetition number: 5 Cycle

* Maximum compression and shear performance test-Vertical load: 6MPa, horizontal displacement: ± 48mm, horizontal repeat cycle: 0.5Hz, horizontal repeat count: 5 Cycle

In addition, Table 9 has shown the result of having tested the maximum displacement (approximately 200%) to the elastic base 10 mentioned above.

Displacement test (200%) Test Items unit Results Equivalent Stiffness kN / m 2287.4 Equivalent decay rate % 17.3 EDC Area kN.m 11.219 Appearance (breakage failure-crack)
-
clear

As described above, the elastic bearing 10 according to the present invention showed good stiffness and damping rate in various conditions of testing.

On the other hand, Figure 2a, 2b discloses an elastic support according to a second embodiment of the present invention. 2A and 2B, the upper and lower edges of the elastic pad 40 are preferably formed with an inclined surface 44 or a curved surface 46 concave inward. The inclined surface 44 or the curved surface 46 prevents the edges of the elastic pad 40 from lifting from the upper and lower plates 20 and 30. That is, the load is transmitted to the elastic support 10 so that the inclined surface 44 or the curved surface 46 is flexibly deformed at the horizontal displacement of the elastic pad 40 so that the edge is not lifted.

Meanwhile, FIGS. 3 and 4 disclose an elastic bearing according to a third preferred embodiment of the present invention.

3 and 4, in the elastic support according to the third embodiment, the coating grooves 28.38 having a predetermined depth in the regions except for the corner portions C of the upper and lower plates 20 and 30, respectively. It is formed, and each of the coating grooves 28 and 38 has a configuration in which the upper and lower portions of the elastic pad 40 and the integrated parts 29 and 39 integrated with each other are inserted and coated. That is, the coating grooves 28 and 38 are formed in the area except the corner portion C, and in this state, the extension 29 in which the rubber constituting the elastic pad 40 is filled in the coating grooves 28 and 38. 39 is the same as the above-described embodiment except that the elastic pad 40 is integrated with the configuration.

At this time, the surfaces of the corner portion C and the extension portions 29 and 39 are horizontally formed without being spaced apart from each other. The coating grooves 28 and 38 are formed in the upper and lower plates 20 and 30 as described above, and the extension portions 29 and 39 integrated with the elastic pad 40 are coated on the coating grooves 28 and 38. By being filled, the upper and lower edges of the elastic pads 40 in contact with the upper and lower plates 20 and 30 are prevented from being lifted up, and a coating effect is obtained so that the work of applying the rust-preventive coating can be omitted.

Meanwhile, as shown in FIG. 4, inclined surfaces 44 may be formed at upper and lower edges of the elastic pad 40, and may be replaced with curved surfaces 46.

While specific embodiments of the invention have been described and illustrated above, it is to be understood that the invention is not limited to the described embodiments, and that various modifications and changes can be made without departing from the spirit and scope of the invention. It is self-evident to those who have. Therefore, such modifications or variations are not to be understood individually from the technical spirit or point of view of the present invention, the modified embodiments will belong to the claims of the present invention.

<Description of the symbols for the main parts of the drawings>
10: elastic support 20: upper plate
30: lower plate 40: elastic pad
42: reinforcing plate 44: inclined surface
46: curved surface

Claims (6)

As a high damping rubber composition,
10-23 weight percent natural rubber;
19-21 wt% butyl rubber;
8-10 weight percent barium lactate;
33-35 weight percent calcium carbonate;
10-12 weight percent carbon black;
4-7 wt% carbon fiber powder; And
A high-damping rubber composition comprising 3 to 5% by weight of an additive. The method of claim 1,
The additive,
35-45 weight percent softener;
35-38 weight percent dispersant;
9-12 weight percent zinc oxide;
5-6% magnesium oxide;
3-4 weight percent antioxidant;
0.5-1.5% by weight of accelerator; And
High damping rubber composition, characterized in that it comprises 2.5 to 3.5% by weight of sulfur. Lower plate 30;
Upper plate 20; And
In the state in which a plurality of reinforcing plate 42 is disposed at equal intervals between the upper and lower plates 20 and 30 to the elastic pad 40 which is vulcanized and bonded to the upper and lower plates 20 and 30. But
The elastic pad 40, the elastic support, characterized in that made of a high damping rubber composition according to claim 1. The method of claim 3,
An elastic support, characterized in that the upper and lower edges of the elastic pad 40, the inclined surface 44 inclined outward or the curved surface 46 concave inward is formed. The method of claim 3,
Coating grooves 28.38 having a predetermined depth are formed in regions except the corners C of the upper and lower plates 20 and 30, respectively.
Each of the coating grooves (28, 38) is elastic support, characterized in that the coating is inserted into the extension portion (29,39) integrated with the upper and lower portions of the elastic pad 40, respectively. The method of claim 5,
Elastic support, characterized in that the upper and lower edges of the elastic pad 40, the inclined surface 44 inclined outwardly or the curved surface 46 concave inwardly.

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