KR101629139B1 - Piezoelectric conductive rubber composition and production method - Google Patents

Abstract

The present invention relates to a conductive piezoelectric rubber composition and a production method thereof. According to the present invention, by recycling waste rubber and using a piezoelectric composition having strong conductivity resistance, the composition can be applied to a vibration detection sensor. By developing a cost-effective and highly sensitive sensor material after producing conductive piezoelectric rubber, it is possible to produce a cost saving type conductive rubber material.

Description

TECHNICAL FIELD [0001] The present invention relates to a conductive rubber composition,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric rubber composition applicable to a vibration sensor, and more particularly, to a conductive piezoelectric rubber composition having high piezoelectric properties by regenerating a waste rubber and a method of manufacturing the same.

Globally, there is growing interest in recycling waste as a means of reducing industrial waste due to global warming environmental problems and resource depletion,

Most of the recycled wastes are difficult to collect at the collection stage due to their diversity of origin and scattering. On the other hand, waste tires are mainly concentrated in junkyard, tire sales and repair shops, relatively easy to recover, .

The waste tire is processed to produce a PCR material.

These PCR materials are used in a limited range, such as on / off switches and safety breakers using pressure, and development of PCR materials for detecting vibration that can detect both pressure and vibration is not enough.

In recent years, electronic products such as mobile communication terminals and digital cameras have been miniaturized, and accordingly electronic components used in electronic products have become very small.

In order to keep pace with the miniaturization of the above-described electronic components, the trend of recent component development is to fabricate an ultra-small and lightweight stacked chip device using a thick film process.

At this time, an Ag-Pd alloy, which is a noble metal, is used as an internal electrode in fabricating the laminated device, but the cost of the parts is high.

The use of non-metallic Ni, which is a noble metal such as an expensive Ag-Pd alloy, can lower the cost and lower the electrical resistance. However, Ag-Pd alloy is easily oxidized during sintering.

On the other hand, piezoelectric materials mainly used are (Pb, Zr) TiO3 (hereinafter referred to as PZT).

However, PZT is contained in an amount of about 65% (by weight) or more of Pb, and is a material to be environmentally regulated.

For example, in accordance with the European Union's Directive on the Use of Hazardous Substances (RoHS), in July 2006 it announced the ban on the use of heavy metals, including Pb, in electrical and electronic equipment. Currently, these guidelines are reserved until alternative substances are developed.

For this reason, active research is currently being conducted on Pb-free piezoelectric materials.

The lead-free piezoelectric material is a (K, Na) NbO 3 (hereinafter referred to as KNN) system having a relatively high electromechanical coupling coefficient, a high phase transition temperature 420 and a high remanent polarization.

However, the lead-free piezoelectric material can not obtain the electromechanical coupling coefficient and the mechanical quality coefficient as much as the presently required expectation, and a more improved piezoelectric rubber could not be obtained.

Korean Patent No. 1322838

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a conductive piezoelectric rubber composition which can be used in a vibration sensor by using a piezoelectric composition having high resistance to electric conduction by recycling waste rubber.

Another object of the present invention is to provide a conductive piezoelectric rubber composition applicable to a vibration sensor capable of improving efficiency and economical efficiency of a manufacturing process due to a simple mixing process, and a method of manufacturing the same.

In order to achieve the above object, the conductive piezoelectric rubber composition of the present invention is produced by mixing 10 to 20 parts by weight of waste rubber, 60 to 80 parts by weight of binder and 10 to 20 parts by weight of metal powder.

At this time, the metal powder may be composed of black carbon and nickel or black carbon and copper.

On the other hand, the method for producing the conductive piezoelectric rubber composition of the present invention comprises: a pulverizing step of pulverizing waste rubber, black carbon and nickel or waste rubber, black carbon and copper into 1 to 250 micrometers; A drying step of drying the pulverized material pulverized in the pulverization step at 50 to 80 ° C for 36 to 60 hours; A step of mixing the pulverized material dried in the drying step with a binder and agitating at a speed of 200 to 500 rpm for 10 to 30 minutes; A molding step of molding the agitated mixture in a stirring step; And a molding step for drying the molded mixture for 12 to 48 hours to produce a product; .

The conductive piezoelectric rubber composition and the manufacturing method thereof according to the embodiment of the present invention have developed a cost sensitive low-sensitive type sensor material by manufacturing a piezoelectric rubber having conductivity by using waste rubber, so that a pressure sensitive rubber material, The sensor can be developed.

1 is a flowchart showing a method of manufacturing a conductive piezoelectric rubber according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the preferred embodiments of the present invention will be described below, but it is needless to say that the technical idea of the present invention is not limited thereto and can be variously modified by those skilled in the art.

1 is a flow chart showing a method of manufacturing a conductive piezoelectric rubber.

As shown in the figure, the conductive rubber composition according to an embodiment of the present invention is prepared by mixing 10 to 20 parts by weight of waste rubber, 60 to 80 parts by weight of binder, and 10 to 20 parts by weight of metal powder.
The binder is generally added to increase the strength of a product by imparting elasticity and tackiness to the sample when the powder is formed in the fields of pharmaceuticals and catalysts. In the present invention, It is preferable to use polyurethane.

At this time, the metal powder may be composed of black carbon and nickel or black carbon and copper.

The conductive rubber composition thus constituted is produced according to the following production method.

Example 1: Grinding step

Waste rubber, black carbon and nickel or waste rubber, black carbon and copper are pulverized to 1 to 250 micrometers.

At this time, waste rubber can be used as waste rubber.

The metal powder is mixed with black carbon and nickel or black carbon and copper to impart conductivity.

The reason why the black carbon is used as a fixing additive is that the black carbon is relatively inexpensive as compared with the copper or nickel, so that the economic effect can be expected.

Black carbon has high thermal shock resistance and heat conductivity due to its low coefficient of thermal expansion and high thermal conductivity. Nickel has excellent corrosion resistance and heat resistance.

Copper is a metal with a safe conductivity at room temperature.

This is because a high sensitivity sensor sensitive to small pressure or vibration must react with pressure or vibration beforehand, and therefore various conductive and low-conductivity fillers must be mixed and mixed.

In the pulverization step, pulverization is carried out until the same particle size is classified as fine particles.

Example 2: Drying step

The pulverized pulverized product is dried at 50 to 80 ° C for 36 to 60 hours.

The pulverized pulverized material is dried in a dryer at a temperature of 50 to 80 ° C for at least 36 to 60 hours.

At this time, if powder mixed with the fine particles is mixed, a chemical reaction may occur, and thus a properly constructed conductive piezoelectric rubber composition can not be formed.

Example 3: Stirring step

The dried pulverized material is mixed with a binder and agitated at a rotating speed of 200 to 500 rpm for 10 to 30 minutes.

The mixture of the waste rubber powder and the conductive filler is mixed with a binder.

At this time, the dispersing agent used is composed of a modified polyurethane in order to lower the viscosity.

The material is mixed for about 15 minutes at 300 rpm through a stirrer based on the selected addition rate during mixing.

Example 4: Molding step

The stirred mixture is molded.

A typical molding method employed by a typical technician is used.

Example 5: Processing step

The molded mixture is dried for 12 to 48 hours to produce a product.

The dried mixture is put into a mold and dried to produce and process the product.

Prototype composition ratio Prototype S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 Waste rubber 18 17 16 15 18 17 16 15 19 Binder 72 68 64 60 72 68 64 60 76 Carbon black 4 4 4 4 4 4 4 4 4 Dispersant One One One One One One One One One nickel 5 10 15 20 - - - - - Copper - - - - 5 10 15 20 - Total 100 100 100 100 100 100 100 100 100

Table 1 shows the composition ratio of the prototypes by increasing the ratio of the conductive filler to the piezoelectric rubber.

The surface resistivity and the resistance value by the distance were tested with the prototype produced through each composition ratio.

Measure prototype surface resistance division 1 time Episode 2 3rd time 4 times 5 times Min. Max. Aver. front rear front rear front rear front rear front rear S-1 10 ¹² 10 ¹⁰ 10 ¹² 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹¹ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹² 10 ¹¹ S-2 10 ¹⁰ 10 ¹⁰ 10 ⁹ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ⁹ 10 ¹⁰ 10 ¹⁰ S-3 10 ⁷ 10 ⁷ 10 ⁷ 10 ⁷ 10 ⁸ 10 ⁷ 10 ⁸ 10 ⁷ 10 ⁷ 10 ⁷ 10 ⁷ 10 ⁸ 10 ⁷ S-4 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁷ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁷ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁷ 10 ⁶ S-5 10 ⁹ 10 ⁹ 10 ⁹ 10 ⁹ 10 ⁹ 10 ⁹ 10 ⁸ 10 ⁹ 10 ⁹ 10 ¹⁰ 10 ⁸ 10 ¹⁰ 10 ⁹ S-6 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁷ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁶ 10 ⁷ 10 ⁶ S-7 10 ⁵ 10 ⁵ 10 ⁶ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁶ 10 ⁵ 10 ⁶ 10 ⁵ 10 ⁵ 10 ⁶ 10 ⁵ S-8 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ 10 ⁵ S-9 10 ¹⁰ 10 ¹¹ 10 ¹² 10 ¹² 10 ¹⁰ 10 ¹² 10 ¹² 10 ¹⁰ 10 ¹² 10 ¹¹ 10 ¹⁰ 10 ¹² 10 ¹¹

Table 2 shows that the prototype 9 without the conductive filler except carbon black had a surface resistivity of 10 ^{12 and} the resistance value was 10 ⁵ when the content of copper was 20%.

It can be seen that the surface resistivity gradually decreases as the content of nickel and copper, which are conductive fillers, increases.

Resistance measurement by separation distance Street
(mm) Number of times S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 10 One 234.5 152.4 110.8 10.22 516 291.3 126 15.59 691 2 198.6 160.8 148.6 9.46 451 551 117.8 33.47 321.4 3 212.5 182.5 104.8 5.8 445.5 215 103.7 51.5 681 4 227.2 176.1 143.4 5.34 594.8 455 225.7 50.2 515 5 190.3 168.9 115.9 6.46 514 441 72.5 54.7 652 Aver. 212.62 168.14 124.7 7.456 504.26 390.66 129.14 41.092 572.08 20 One 369.4 302.4 124.2 4.121 514.4 375 82 31.24 744 2 384.6 248.9 155.7 4.28 561.8 437 161.3 64.6 425 3 401.2 264.1 142.9 12.31 582 410 112.5 80.3 754 4 376.5 224.5 160.8 9.86 311.3 513 251.9 82.3 926 5 398.7 300.4 174.8 8.47 642 621 136.2 85.4 893 Aver. 386.08 268.06 151.68 7.8082 522.3 471.2 148.78 68.768 748.4 30 One 553.2 512.4 409.1 9.46 951 809 134.3 18.04 1770 2 586.2 498.6 417.4 9.841 846 820 239.8 81.4 527 3 561.9 488.1 395.2 17.87 895 603 151.4 82.4 925 4 579.8 524 407.3 13.42 910 966 446.3 94.6 1322 5 594.2 509.6 382.3 12.66 932 867 255.4 80.2 1554 Aver. 575.06 506.54 402.26 12.65 906.8 813 245.44 71.33 1219.6 40 One 776 715 552.4 7.76 1215 1140 127.8 52.3 2109 2 761 654 601 8.651 1320 855 291.9 95.3 780 3 788 642 693 16.58 987 716 227.6 70.5 1410 4 813 594.8 611 18.48 1052 1054 510.8 108.23 2117 5 786 685 455.3 8.16 1134 1032 433 125.4 3800 Aver. 784.8 658.16 582.54 11.92 1141.6 959.4 318.22 90.35 2043.2 50 One 921 822 722 6.31 1320 1950 140.4 78 1620 2 937 794 734 9.814 1248 1316 266.5 101.5 1891 3 908 832 756 25.18 1684 837 249.1 75.2 1567 4 894 816 754 11.53 1432 1164 714 158.4 2876 5 996 795 812 10.3 1542 1540 492 175.1 2690 Aver. 931.2 811.8 755.6 12.62 1445.2 1361.4 372.4 117.64 2128.8

As shown in Table 3, the resistance value is similar to the surface resistance value as a result of the resistance value measurement by the separation distance, and the resistance value increases as the separation distance increases.

In the case of copper-doped prototypes, the S-5 added with 5% had a somewhat higher resistance but the S-8 with the added 20% showed the lowest resistance.

Unlike the surface resistance value, the S-4 (20%) resistance with the highest nickel content is the lowest in the contact resistance value measurement result.

As a result of measuring the resistance value by the surface resistance and the separation distance, it is possible to produce a flexible, light, and conductive piezoelectric rubber as the resistance value decreases according to the house due to the high addition amount of the conductive filler.

It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings . The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as falling within the scope of the present invention.

Claims (3)

10 to 20 parts by weight of waste rubber;
60 to 80 parts by weight of a binder; And
And 10 to 20 parts by weight of a metal powder.
The method according to claim 1,
Wherein the metal powder is composed of black carbon and nickel or black carbon and copper.
A pulverizing step of pulverizing waste rubber, black carbon and nickel or waste rubber, black carbon and copper to 1 to 250 micrometers;
Drying the pulverized pulverized product in the pulverizing step at 50 to 80 ° C for 36 to 60 hours;
Mixing the pulverized material dried in the drying step with a binder and stirring at 200 to 500 rpm for 10 to 30 minutes;
A molding step of molding the stirred mixture in the stirring step; And
A processing step of producing a product by drying the molded mixture in the molding step for 12 to 48 hours; Wherein the conductive rubber is a thermoplastic elastomer.

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