KR101720014B1 - Porous Pressure-Sensitive Rubber and Products Comprising the Same - Google Patents

Abstract

The present invention relates to a porous pressure-sensitive rubber for a seat of a vehicle and a processed article comprising the same. More particularly, the present invention relates to a porous pressure-sensitive rubber comprising pores-containing silicone rubber and multi-walled carbon nanotubes, and a vehicle seat or wearable device comprising the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a porous pressure-sensitive rubber and a processed product including the porous pressure-

The present invention relates to a porous pressure-sensitive rubber for a seat of a vehicle and a processed article comprising the same. More particularly, the present invention relates to a porous pressure-sensitive rubber comprising pores-containing silicone rubber and multi-walled carbon nanotubes, and a vehicle seat or wearable device comprising the same.

BACKGROUND ART Various devices for realizing a method of recognizing a load applied to a seat of a vehicle are widely used in vehicles. This is because the safety and comfort of the vehicle can be increased through such a device. Such a load recognizing device is operated in conjunction with an airbag which is a safety function of a vehicle or a heater for a seat which is a convenience function, and the operation of a specific function linked with the load recognizing device is determined or adjusted through the load of the passenger.

German patent DE 196 15321 discloses the operation of a differential air bag according to the seat load. At the same time, it is intended to recognize whether or not an adult, a child, or a child seat exists in the seat of the vehicle. Other stabilizers, such as seatbelt systems or roll-bar systems, are being regulated by a pressure-sen- sor-type device installed in the seat.

In addition, the adjustment function of the special seat position and the safety function associated with the seat are generally adjusted through the pressure acting on the seat manually by the passenger. Such a system is disclosed in German patent DE 43 39 113, which has a function of adjusting the position of the head restraint and a safety feature for children about the door and the window of the rear magnet, as well as another function, for example lighting function, And a climate control function that operates according to the load.

In recent years, a welcome system has been widely used, for example, in which a driver illuminates a vehicle to improve the driver's mood when boarding the vehicle. To utilize such a system, the driver senses the load when the driver sits, To work.

The sensitivity of mechanical sensors (e.g., pressure sensors and strain gauges) to sense the load on the sheet is one of the most important performance factors.

The use of transistors for signal amplification is an effective method for this particular purpose. Another method for high sensitivity is to measure capacitive change instead of resistance change, or use a specially designed interlocking structure. However, these methods generally require complicated micro-fabrication processes.

Resistive mechanical sensors are based on simple operating principles, that is, measuring the resistance of a material. Pressure sensitive rubber (PSR), typically a composite of an elastomer and a conductive filler such as carbon black and carbon nanotubes, is widely used as a material for flexible resistance mechanical sensors.

Since only two components (piezoelectric materials and electrodes) are required for the detection of mechanical deformation, the device structure and manufacturing process are relatively simple. Due to the elasticity of the PSR, the PSR can be used in combination with a flexible and stretchable substrate and an inflatable surgical instrument in a compatible manner and can be easily integrated into a smooth, curved surface including the human body. However, conventional PSR based sensors often suffer from low sensitivity.

Conventional methods for producing pressure sensitive rubbers include injecting a conductive filler into an elastic polymer. Polyurethane, PDMS, or the like is used for the elastic polymer, and CNT, graphene, carbon black powder and the like are used for the filling material.

One way to increase the sensitivity is to introduce a porous structure into the piezoelectric material. The change in resistance of a PSR-based mechanical sensor at a particular force depends on the modulus and deformability associated with the PSR. In order to increase this strain, sponge-like structures have been proposed ( ACS . Nano . 2010 , 4, 2320.).

For example, hollow spherical conductive polymers, porous carbon nanotube sponges, metal-polymer hybrid nanocable sponges, and gold film-polyurethane sponges have enhanced sensitivity to the detection of mechanical deformation. However, in the conventional method, the size, volume ratio, uniformity, etc. of voids can not be controlled in the sponge structure. In addition, when the chemical vapor deposition method or the immersion plating method is used, the process is very difficult, and it is difficult to commercialize it because it is difficult to make it into a large area ( ACS . Nano . 2010 , 4, 2320.).

Yao et al . ( Adv . Mat . 2013 , 25, 6692) synthesized an electrically conductive polyurethane sponge by carrying graphene oxide on a sponge-type polyurethane and then reducing it. In contrast to Yao et al., The present invention differs in that the conductive rubber is synthesized through a liquid phase reaction.

The present inventors have found that the pressure (or load) applied to a seat, a fabric, a film, a garment, a band, a string or the like is reduced by using a pressure-sensitive rubber capable of controlling the size and uniformity of pores by a liquid- So that the present invention has been completed.

A fundamental object of the present invention is to provide a porous pressure-sensitive rubber comprising a silicone rubber containing pores and a multi-walled carbon nanotube.

A further object of the present invention is to provide a sheet made of porous pressure sensitive rubber, in particular a sheet, fabric, film, garment, band, string or the like for a vehicle.

The present invention can be achieved by providing a porous pressure-sensitive rubber comprising the silicone rubber containing the basic pores of the present invention and the multi-walled carbon nanotube described above.

In one embodiment, the present invention provides a porous pressure sensitive rubber for use in sensing pressure on a seat of a vehicle.

A seat of a general automobile includes a seat cushion in which an occupant sits, a seat back supporting the backrest of the occupant seated on the seat cushion, and a head rest provided at the upper end of the seat back to support the head of the occupant. Under the seat cushion, there is provided an adjustment lever which can adjust the position of the seat by moving the seat forward and backward. The seat cushion and the seat back are fixed by a hinge. The connecting portion between the seat cushion and the seat back is generally provided with an inclination adjusting lever for adjusting the inclination of the seat back.

The pressure applied to the seat can be measured by applying the porous pressure-sensitive rubber according to the present invention to a seat cushion, a seat back or a headrest. The porous pressure-sensitive rubber may be applied to the outer surface of a seat cushion, a seat back or a headrest or a lower portion of the outer surface of the outer cover.

The porous pressure-sensitive rubbers of the present invention include all of the various natural or synthetic rubbers commercialized and known in the art until the filing date of the present application. In particular, the porous pressure-sensitive rubber of the present invention may include silicon rubber containing pores and multi-walled carbon nanotubes. Particularly, the rubber of the present invention includes all natural or synthetic viscoelastic materials known as silicone rubber, nitrile rubber, SBR rubber, urethane rubber, urethane skin foam and the like.

Using the piezoelectric phenomenon of the porous pressure-sensitive rubber, the pressure is measured by the magnitude of the generated current or the corresponding voltage when the pressure is applied.

The size of the pores contained in the porous pressure-sensitive rubber of the present invention is preferably 100 μm to 2 mm.

Polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polyphenylmethylsiloxane, or polyphenylethylsiloxane resin is particularly suitable as the silicone rubber included in the porous pressure-sensitive rubber of the present invention, Includes all silicone rubbers known in the art.

The pressure-sensitive rubber of the present invention may be selected from various synthetic resins known to exhibit physical properties as a viscoelastic material at a high temperature or below room temperature. Among them, silicone rubber, urethane rubber, nitrile rubber and natural or synthetic SBR rubber are particularly suitable .

The diameter of the multi-walled carbon nanotubes is preferably 1 nm to 2 nm, and the length is preferably 10 μm to 20 μm. The multi-wall carbon nanotubes are dispersed in the silicone rubber to impart electrical conductivity to the porous pressure sensing rubber.

Another object of the present invention is to provide a sheet made of porous pressure-sensitive rubber, particularly a sheet for a vehicle, a fabric, a film, a garment, a band, a string, have.

In one embodiment, the present invention provides a vehicle seat comprising a porous pressure sensitive rubber.

The porous pressure-sensitive rubber included in the vehicle seat of the present invention may include silicon rubber containing pores and multi-walled carbon nanotubes. The porous pressure sensitive rubber may also be in the form of a film or fabric. Using the piezoelectric phenomenon of the porous pressure-sensitive rubber, the pressure is measured by the magnitude of the generated current or the corresponding voltage when the pressure is applied.

The pore size of the silicone rubber contained in the vehicle seat of the present invention is preferably 100 μm to 2 mm.

The silicone rubber contained in the vehicle seat of the present invention may be polydimethylsiloxane or polydiethylsiloxane.

The diameter of the multi-walled carbon nanotubes is preferably 1 nm to 2 nm, and the length is preferably 10 μm to 20 μm. The multi-wall carbon nanotubes are dispersed in the silicone rubber to impart electrical conductivity to the porous pressure sensing rubber.

The pressure applied to the seat can be measured when the entire or a part of the outer surface of the seat cushion, the seat back, or the headrest of the vehicle seat of the present invention is made of a film or fabric made of a porous pressure sensitive rubber. A film or fabric made of the porous pressure-sensitive rubber may be disposed under the outer surface of the seat cushion, the seat back, or the headrest.

In another embodiment, the present invention provides a film made using a porous pressure sensitive rubber. The method of producing the film is illustrated in Example 2 below.

In another embodiment, the present invention provides a fabric made using a porous pressure sensitive rubber. The method of making the fabric is illustrated in Example 3 below.

The fabric may be used to produce pressure sensitive garments. In the case of the pressure-sensitive garment, it can be applied to detect the operation of the wearer.

In addition, the present invention provides a band that can be worn on the wrist, ankle, forehead, etc. using a porous pressure sensitive rubber. The pulse can be measured using the pressure sensing properties of the band.

Further, the porous pressure-sensitive rubber according to the present invention can be used to provide a one-dimensional article such as a rubber strip.

In another embodiment, the porous pressure-sensitive rubber of the present invention can be applied to a cover for packaging automobiles or other important objects. When any type of force including impact is applied to the cover, the cover can sense the force, that is, the pressure, and transmit it as an electrical signal.

The porous pressure-sensitive rubber of the present invention can be applied to various fields requiring measurement of pressure (or load) by applying it to a seat, fabric, film, clothes, band, string or the like.

Particularly, by providing the porous pressure-sensitive rubber capable of measuring the pressure applied to the vehicle seat of the present invention, it is possible to measure whether or not the occupant is seated on the seat and the weight of the occupant. This can determine whether the airbag in the vehicle is operating and whether other convenience equipment such as a welcome system is operating.

1A is a diagram showing mixing steps of a multi-wall nanotube (MWNT), a reverse micelle solution (RMS) and a PDMS in a method of the present invention, FIG. 1B illustrates a mold molding method for producing a PPSR film, Shows a nozzle jet printing method for forming a PPSR pattern, and FIG. 1D shows the behavior of reverse micelles during a heat treatment process.
Figure 2A shows the micros for PPSR at different RMS volumes (4 mL, 6 mL, 8 mL) and molecular weights (86.2 g / mol, 100.2 g / mol, 114.2 g / mol for hexane, heptane, FIG. 2B is a three-dimensional stacking of μ-CT images of PPSR prepared with hexane-based RMS 4 mL (left) and octane-based RMS 4 mL (right) at different depths, CT image, and Figure 2C is a plot of the permeation mode (front) and opaque mode (right) versus 8 mL (left) of hexane-based RMS (left), 8 mL 3-D finite element model for PPSR using solid mode (rear).
FIG. 3A is a photograph of a large area PPSR-based pressure sensitive fabric, FIG. 3B is a photograph showing the reversible compressibility of stacked PPSR films, FIG. 3C shows a resistance change response of a pressure sensitive fabric to an external pressure, The inset of FIG. 3C illustrates tapping (left), knocking (centering), and hitting (right) modes.
FIG. 4A is a photograph of a car seat provided with a fabric made of the PPSR-based pressure-sensitive rubber of the present invention, and FIG. 4B is a photograph showing a load applied to the car seat when the driver is seated on the car seat.
Figure 5 shows the resistance change over time of the PPSR-based pressure sensitive fabric attached to the cushion, backrest and headrest of the seat when the driver sits on the seat or stands out of the seat.

Hereinafter, the present invention will be described in more detail with reference to the following examples or drawings. It is to be understood, however, that the following description of the embodiments or drawings is intended to illustrate specific embodiments of the invention and is not intended to be exhaustive or to limit the scope of the invention to the precise forms disclosed.

Example  1. Black Gel-like  Preparation of mixtures

20 mL of octane (98%, Sigma-Aldrich, USA), 2 g of emulsifier (Polyoxyethylene (5) nonylphenyl ether, branched, Igepal CO-520, M _n : 441, Sigma Aldrich, USA) Was stirred for 30 minutes to prepare a reversed micellar solution. 0.1 g of a multi-wall nanotube (MWNT) (HANOS CM-250, Hanwha Nanotech, South Korea) and 9 g of poly (dimethylsiloxane) (PDMS) (30: 1 mixture of prepolymer and curing agent ; Sylgard 184, Dow Corning, USA) were mixed with 0 to 8 mL of the reverse micellar solution. The mixture was sonicated for 30 minutes each and agitated for 30 minutes to obtain a black gel-like solution (FIG. 1A). As a result, MWNTs were homogeneously distributed in the viscous medium to form uniform reverse micelles. The reversed micelle is a water droplet surrounded by an emulsifier and an organic solvent, and a PDMS mixture, an organic solvent and an MWNT exist outside the reversed micelle (right lower portion of FIG. 1A).

Example  2. Film manufacturing and Patterning  Way

For the production of the pressure sensitive film, the black gel-like porous pressure sensitive rubber (PPSR) prepared in Example 1 was poured into a template to prepare a film (FIG. 1B). Thereafter, the filled mold was covered with glass. By covering the black gel-like PPSR during the heat treatment, the uniformity of the pores could be increased.

For patterning of PPSR, a well mixed black gel-like PPSR was filled in a 6 mL syringe and mounted in a nozzle jet printing system (eNano Printer, Enjet, South Korea). The black gel-like PPSR was sprayed from a nozzle onto a target substrate to form a ly pattern (Fig. 1C). Customized software was used to control the movement of the nozzle. A patterned black gel-like PPSR surrounded by a dam and silicone oil (Shin-Etsu silicone, Japan) was poured into the dam to cover the pattern. Finally, the PDMS was solidified by heat treatment in an oven to form a pore structure, and the silicone oil was removed. Figure 1D shows a high-resolution photograph of the process. The temperature of the heat treatment step was increased stepwise (Table 1). In the heat treatment step, the reversed micelles move, combine, and evaporate to obtain a pore structure. The sample thus obtained was then repeatedly washed with isopropyl alcohol and deionized water.

The micro-computed tomography (μ-CT) photograph of FIG. 2A shows a PPSR (μ-CT) image generated using different solvents (hexane, heptane and octane) and varying amounts of RMS (4 mL, 6 mL and 8 mL) Of the pore structure. As the boiling points of the solvents increased, the PPSR showed larger pore size and higher porosity. Similar trends were observed when increasing the amount of RMS. Figure 2B shows three-dimensional tomographs at different depths (0 mm, 0.5 mm, 1.0 mm and 1.5 mm) and their combined photographs (top) for PPSRs made using hexane and octane. In addition, the amount of conductive filler also affected the pore size. The smaller the pore size, the more uniform piezoresistive chraracteristics. The three-dimensional finite element model of PPSR (Figure 2C) fitted well with the experimental data (Figures 2A and 2B).

Heat treatment temperature and time Hexane Heptane octane 55 ° C, 12 hr
60 ° C, 0.5 hr
65 ° C, 3 hr
70 ° C, 1 hr
80 ° C, 1 hr
90 ° C, 1 hr
120 ° C, 3 hr 55 ° C, 12 hr
70 ° C, 3 hr
80 ° C, 0.5 hr
85 ° C, 3 hr
90 ° C, 1 hr
100 ° C, 1 hr
120 ° C, 3 hr 55 ° C, 12 hr
70 ° C, 3 hr
90 ° C, 1 hr
100 ° C, 1 hr
110 ° C, 0.5 hr
115 ° C, 3 hr
120 ° C, 3 hr

Example  3. Manufacture of pressure sensitive fabrics

A large area (23 cm x 16 cm) PPSR film (Fig. 3A) was prepared by inserting the PPSR film prepared in Example 2 between two commercially available conductive carbon fabrics (W0S1002, CeTech, Japan). For the conformal contact between the PPSR film and the carbon fabric, a binder (conductive rubber paste) consisting of 0.2 g of MWNT and 9 g of PDMS was used (the inset of FIG. 3A). Different strains in laminated PPSR films are shown in Figure 3B. The PPSR film can be compressed and easily restored to its original shape by removing the applied pressure. To further evaluate the mechanical reliability of the pressure sensitive fabric, cycle tests were performed. As a result, PPSR showed the same modulus and resistance change response at repeated compression (about 30% strain, about 10 kPa pressure). As shown in FIG. 3C, the pressure sensitive fabric has successfully distinguished repeatedly different pressures (50 kPa, 130 kPa, 260 kPa), which makes the pressure sensitive fabric a smart wearable product such as a pressure sensitive garment wearable products.

Example  4. Car seat with pressure sensitive fabric

As shown in Figure 4A, the pressure sensitive fabric (PPSR sensor) made in Example 3 was attached to the cushion, seat back and head rest portions of the car seat. Further, a wireless communication system (Bluetooth) was installed inside the automobile seat. The change in resistance of the PPSR pressure sensor was converted to a voltage change using a voltage divider, and the analog voltage signal was converted into a digital voltage signal using an analog-to-digital converter. The voltage change due to the resistance change of the PPSR sensor was wirelessly transmitted to the in-vehicle computer. The wirelessly transmitted voltage information was converted from the computer to resistance information, and the graph shown in FIG. 5 was obtained.

In the sensor of the seat cushion where the load is the greatest, the resistance change is greatest, and the resistance change becomes smaller in the order of the seat back sensor having the second greatest load and the headrest sensor having the smallest load. The seat cushion -> backrest -> headrest shows a peak in the order of seat cushion, seat cushion, backrest, and headrest in descending order The headrest, the backrest, and the seat cushion are displayed in the order of the peak, so that it is possible to distinguish between when the driver sits and when the driver stands up.

Claims (16)

delete delete delete delete A porous pressure sensing rubber including a silicone rubber containing pores formed using a reverse micelle solution and a multiwall carbon nanotube is mounted,
The reversed micelles are produced by stirring at least one of octane, hexane, and heptane, an emulsifier, and deionized water,
The size of the pores is 100 [mu] m to 2 mm,
The multi-walled carbon nanotube has a diameter of 1 nm to 2 nm and a length of 10 μm to 20 μm and is mounted on at least one of a seat cushion, a seat back, and a headrest, (Or load) of the vehicle. 6. The vehicle seat according to claim 5, wherein the porous pressure-sensitive rubber is in the form of a film or a fabric. delete 6. The vehicle seat according to claim 5, wherein the silicone rubber is selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, polyphenylmethylsiloxane, and polyphenylethylsiloxane. delete A porous pressure sensing rubber including a silicone rubber containing pores formed using a reverse micelle solution and a multiwall carbon nanotube is mounted,
The reversed micelles are produced by stirring at least one of octane, hexane, and heptane, an emulsifier, and deionized water,
The size of the pores is 100 [mu] m to 2 mm,
Wherein the multi-walled carbon nanotubes have a diameter of 1 nm to 2 nm and a length of 10 [mu] m to 20 [mu] m. A porous pressure-sensitive rubber comprising silicon rubber and multi-walled carbon nanotubes containing pores formed using a reverse micelle solution,
The reversed micelles are produced by stirring at least one of octane, hexane, and heptane, an emulsifier, and deionized water,
The size of the pores is 100 [mu] m to 2 mm,
Wherein the multi-walled carbon nanotube has a diameter of 1 nm to 2 nm and a length of 10 m to 20 m. A silicon rubber containing pores formed using a reverse micelle solution and a multiwalled carbon nanotube,
The reversed micelles are produced by stirring at least one of octane, hexane, and heptane, an emulsifier, and deionized water,
The size of the pores is 100 [mu] m to 2 mm,
Wherein the multiwall carbon nanotube has a diameter of 1 nm to 2 nm and a length of 10 to 20 μm. Preparing a reversed micellar solution;
Preparing a mixed solution by mixing the reversed micelle solution, the multi-walled nanotube, and poly (dimethylsiloxane);
Ultrasonic treatment of the mixed solution and stirring to prepare a black gel-like solution;
Pouring the black gel-like solution into a mold and covering with a glass; And
Heat treating the black gel-like solution adhered to the template to produce a pore-formed film; And
And placing a commercially available conductive carbon fabric on the top and bottom surfaces of the film. 14. The method of claim 13,
Wherein the step of preparing the reversed micellar solution comprises mixing at least one solvent selected from octane, hexane, and heptane with an emulsifier, followed by stirring. A car seat to which a porous pressure sensitive fabric fabricated by attaching the porous pressure sensitive fabric fabricated by the manufacturing method according to claim 13 to at least one of a cushion, a backrest, and a headrest of an automobile seat is applied. 14. A garment comprising a porous pressure sensitive fabric made by the method of manufacture according to claim 13.

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