KR100840892B1 - Nonwoven oil/water separating fabric material comprising plasma coating layer, and oil/water separating filter comprising the same - Google Patents

Abstract

The present invention relates to an oil and water separation material including a plasma coating layer, and an oil and water separation filter including the same, and more particularly, a surface tension of 3.0 × 10 ⁻² J / m ² to 7.2 on the surface of a nonwoven fabric including polymer fibers. The present invention relates to an oil-separation material having a plasma coating layer of 10 × ^{2 −2} J / m ² , and an oil-water separation filter including the same.

 The oil and water separation material of the present invention is excellent in oil and water separation characteristics that separate water and oil, and excellent in oil durability, and can be used as fuel filters for various automobiles and industrial machines equipped with diesel engines, gasoline engines, and the like. have.

Oil Separation, Fuel, Water, Filter, Plasma, Lotus Structure, Non-Woven

Description

Non-oil-shaped oil-water separation material including a plasma coating layer, and oil-water separation filter comprising the same

1 is an oil separation mechanism of the oil separation material of the present invention.

Figure 2 is a schematic view of the fiber surface showing a fine concavo-convex structure of the present invention of the oil-water separation material of the present invention.

Figure 3 is a schematic diagram comparing the separation characteristics according to the lotus structure.

Figure 4 is a separation test photograph of the oil and water separation material prepared according to Example 2.

5 is a separation test photograph of the oil-water separation material prepared according to Comparative Example 1.

[Industrial use]

The present invention relates to an oil-water separation material including a plasma coating layer, an oil-water separation filter including the same, and a manufacturing method thereof, and more particularly, to a fuel filter such as various automobiles and industrial machines equipped with a diesel engine, a gasoline engine, and the like. An oil separation material that can be used, and an oil separation filter comprising the same.

[Private Technology]

Recently, as environmental problems are greatly highlighted, separation materials for removing contaminated materials are attracting attention, and demand is increasing due to diversification of active research and use fields for high performance and application of separation material functions.

According to the purpose of the separation material, depending on the purpose of separation, the target fluid is classified into dry filtration, which is a gas, and wet filtration, where the target fluid is a liquid, and classified into gas / liquid and liquid / liquid according to the separation function.

Among the separated materials, the largest market is in the field of transportation of automobiles and the like, and the amount of use of various industrial liquid filters, dust filters, air filters, and masks is also increasing.

In the case of liquid / liquid separation or gas / liquid multifunctional separation materials, pulp filters accounted for more than 80% of the existing media market in developed countries such as the United States and Europe, but the market share of synthetic filter media is gradually increasing.

With the recent development of high-performance diesel engines, fuel filter media requires a high degree of water separation performance.

Silicon treated pulp media appeared to provide oil separation function, but there were many problems in satisfying consumers.In case of 5 or more layers of non-woven composite media, better dust removal ability, filtration efficiency and oil separation than conventional pulp media It is known as a product having performance.

In addition, the filtration design technology is shifting from the surface filtration method to the deep filtration mechanism to improve the durability life through increasing the dust removal capacity, and it is necessary to convert it to a fully synthetic fibrous nonwoven fabric instead of cellulose. to be.

There is a continuing demand for environmentally friendly manufacturing processes and materials. Existing phenol / formaldehyde-impregnated cellulose-based fuel filter media has caused an environmental problem due to volatilization during the manufacturing process. Formaldehyde remains in the media and is incorporated into automobile engines, resulting in additional environmental pollution.

Therefore, it is urgent to secure new media manufacturing technology that can solve these problems, and the demand for a clean environment is increasing greatly. In-depth research on the technology of manufacturing the separated materials is required.

Plasma surface treatment technology improves the performance of a material by changing the surface of the polymer material or imparts new functions. The plasma surface treatment technology does not affect the bulk properties of the polymer material, and the modification of the physical and chemical properties of the surface It is expected that the processing of inexpensive materials into expensive materials will increase the importance of plasma surface treatment technology in the future industry.

Since the temperature of ions and neutral particles in the plasma is kept at a low temperature, it is possible to use most polymers that are easily damaged by heat as a base material. Can be functionalized.

The present invention is to solve the above problems, it is an object of the present invention to provide a material having oil and water separation characteristics using the plasma surface treatment.

Another object of the present invention is to provide an oil / water separation filter including the oil / water separation material.

In order to achieve the above object, the present invention provides an oil and water separation in which a plasma coating layer having a surface tension of 3.0 × 10 ⁻² J / m ² to 7.2 × 10 ⁻² J / m ² is formed on a surface of a nonwoven fabric including polymer fibers. Provide the material.

The present invention also provides an oil separation filter including the oil separation material.

The present invention also comprises the steps of preparing a nonwoven fabric comprising a polyamide fiber, and at least one polymer fiber selected from the group consisting of polyester fibers; And plasma treating the surface of the nonwoven fabric in a mixed gas atmosphere containing fluorocarbon gas having 1 to 3 carbon atoms and hydrocarbon gas having 1 to 3 carbon atoms in a volume ratio of 50:50 to 90:10. It provides a method of manufacturing.

Hereinafter, the present invention will be described in more detail.

Generally, particulate water components present in oil components of hydrocarbon components such as diesel and gasoline are dispersed in suspension state or emulsified in emulsion state due to surface tension difference. The particle size of the water component has a diameter of about 0.1 μm to 10 μm, and it is difficult to visually identify it unless it is opaque because it exists in high concentration.

Water present in oil components, such as automotive fuel, is easy to remove in the case of large particle suspensions, but is difficult to remove when emulsified.

Oil-water separation refers to the ability to separate and remove water components present in oil components such as automobile fuels.

Nowadays, the biggest problem of refined fuel is water that is dispersed inside, not solid contaminants. Water in fuel shows great problems such as rusting engine parts, clogging, corrosion of fuel tank bottom, and microorganisms growing. . A water content of around 100 ppm alone will prevent the fuel from functioning.

In general, there is a problem that the interfacial tension between the fuel and water falls to a level that is difficult to separate due to the emulsification by various additives added to the fuel.

Factors affecting oil separation performance include interfacial tension, viscosity, relative density, and temperature.

The interface between the two phases is called the interface, and the force that reduces the area of the interface is called the interface tension. Although it has almost the same meaning as surface tension, interfacial tension refers to a general case, and surface tension is used especially when one phase is gas phase.

Nonpolar hydrocarbon compounds such as diesel and gasoline have a surface tension of 2.18 × 10 ^-2 J / m ² (equivalent to 21.8 dyne / cm, at 25 ° C.), while water is 7.3 × 10 ^-2 J / m ² (73 dyne / It corresponds to cm, and it is known to reach 25 degreeC). In particular, the interfacial tension between these two components is a very important factor in the liquid / liquid phase separation such as fuel / water, in which small droplets dispersed in the fuel by a process called coalescence are stable droplet size. This is because it can be easily separated by growing.

In this case, coalescence is a process in which two or more droplets are gathered to change into a larger volume of droplets and change in a direction having a small area. Thermodynamically, a phenomenon in which multiple particles aggregate together to form one large particle due to the fusion of particle interfaces. As an irreversible process.

Generally, when the interfacial tension is 2.0 × 10 ^-2 J / m ^{2 or more} (corresponding to 20 dyne / cm, based on 25 ° C), the size of the coalesced particles is easily separated, but the interfacial tension is emulsified by the additive in the fuel. If it is less than 2.0 × 10 ⁻² J / m ² , the size of the coalesced particles is so small that it becomes very difficult to separate them.

The oil / water separation mechanism of the present invention maximizes the surface collision mechanism of the water particles and the fibrous particles.

In general, the particles present in the fluid have a characteristic of reaching the solid surface, that is, the surface wetting does not occur when colliding, and the contact time between the water particles and the fibrous surface is too long even when a surfactant is included. it is known that sound is short enough bar (Hartley, GS, & Brunskill, RT in Surface Phenomena in Chemistry and Biology, p 214, JF Danielli Ed, Pergamon Press, 1958;.. Richard, D., & Quere, D. Europhys . Lett 50, 769-775 (2000) ;. Aussillous, P., & Quere, D. Nature 411, 924-927 (2001)).

However, in the case of continuous flow, collisions of water particles in the fuel accumulate and eventually behave according to the unity mechanism on the fiber surface as described above. In particular, a hydrophilic polymer fiber material such as polyester or polyamide may be used. This probability is large.

In the present invention, by coating a material having a very large interfacial tension with water on the fibrous surface and using it as an oil-and-water separation material, water particles in the fuel are continuously bound to the surface of the separating material without binding to the fiber surface as shown in FIG. By staying and continuing to coalesce with subsequently entering water particles, one would like to implement a mechanism that allows the particles to continue to grow and then be separated downward by gravity.

In addition, in the present invention, as shown in FIG. 2, fine irregularities are formed on the surface of the fiber, and then a material having a very large interfacial tension with water is coated to maximize the repulsion of water particles on the surface of the fiber as shown in FIG. In this case, it is possible to implement a very good oil and water separation characteristics compared to the flat structure without fine irregularities.

The present invention relates to a technique for imparting oil and water separation characteristics of the surface by plasma treatment of the surface of the nonwoven fabric.

As a conventional technology for providing separation performance by plasma treatment, only a single function separation performance surface treatment technology that simultaneously imparts water repellency and oil repellency by plasma surface treatment using a fluorine-based gas has been mainly performed. There is a need for a surface treatment technology for providing the same multi-functional resolution.

The surface of lotus leaf or taro leaf having high water repellency shows excellent water repellency due to the characteristics of the cells forming the leaves. That is, the surface cells of these leaves are composed of submicron microstructures and multi-structures composed of relatively large irregularities (several μm) and waxy components (aliphatic compounds having 20 to 50 carbon atoms) of the outer epidermis.

The surface structure of the lotus leaf shows a super water repellency of the contact angle of about 170 ° by the combination of low surface energy of the surface wax component and unevenness of the multi-structure. The water repellency imparting effect according to the physicochemical structure is called a lotus effect. Super water-repellent generally means that the contact angle with respect to water is 140 degree or more.

The oil-water separation material of the present invention is characterized in that a plasma coating layer is formed on a surface of a nonwoven fabric containing polymer fibers.

In particular, in order for the oil-water separation material of the present invention to have super water repellency without changing the oil repellency of the surface, the surface tension of the plasma coating layer should have a value between water and oil surface tension, and specifically, the surface tension of the plasma coating layer It is preferable that it is 3.0 * 10 <^-2> J / m <^2> -7.2 * 10 <^-2> J / m <^2> based on 25 degreeC.

In order for the plasma coating layer to have such a surface tension, the plasma coating layer is formed by plasma vapor deposition of a mixed gas containing fluorocarbon gas having 1 to 3 carbon atoms and hydrocarbon gas having 1 to 3 carbon atoms in a volume ratio of 50:50 to 90:10. It is preferable to form, and the volume ratio of the mixed gas is more preferably 70:30 to 80:20. Since the surface tension of the plasma coating layer decreases as the content of the fluorocarbon gas increases in the mixed gas of the present invention, the surface tension of the coating layer may be controlled by controlling the content ratio of the mixed gas. Examples of the fluorocarbon gas include C ₂ F ₆ , or C ₃ F ₆ , and CH ₄ may be used as the hydrocarbon gas.

The nonwoven fabric included in the oil-separation material of the present invention preferably comprises at least one fiber selected from the group consisting of polyamide fibers and polyester fibers, and the polyamide fibers include nylon 6, nylon 6.6, and nylon 4.6. More preferably, at least one polyamide fiber selected from the group consisting of nylon 6.10, nylon 6.12, nylon 11, nylon 12, and two or more copolymers thereof, wherein the polyester fiber is polyethylene terephthalate, polybutylene More preferably, it is at least one polyester fiber selected from the group consisting of terephthalate, polyethylene naphthalate, and two or more copolymers thereof.

However, the type of the polymer fiber in the present invention is not limited only to the above examples, polyolefin fiber, polyacrylonitrile fiber, cellulose fiber, polyether sulfone fiber, etc., which have excellent oil resistance, may be used alone or in combination, if necessary. Can be.

The type of the nonwoven fabric is not particularly limited, but is preferably a nonwoven fabric produced by a spunbond method, a melt blown method, a flash spinning method, a hydroentangle method, or the like.

It is preferable that the said polymer fiber is 1-10 micrometers in average diameter, and it is more preferable that it is 1-5 micrometers in average diameter.

In addition, it is more preferable that irregularities are formed on the surface of the polymer fiber of the nonwoven fabric in terms of controlling capillary force. The unevenness may be formed on the surface of the polymer fiber included in the nonwoven fabric by a method of plasma etching the surface of the nonwoven fabric.

The oil-water separation material of the present invention may be manufactured by a method of forming a plasma coating layer on the surface of a nonwoven fabric using a low temperature and low pressure plasma surface treatment apparatus using an RF plasma source. However, the manufacturing method of the present invention is not limited only to the above contents.

The nonwoven fabric structure is not particularly limited within the range satisfying the above conditions, but is made of staple fibers and manufactured by a method such as a needle punching method, a thermal bonding method, a hot air bonding method, a hydroentanglement method, or a spun that is a direct spinning method. It is manufactured by the bond method, the melt blown method, or the flash spinning method, and can be used alone or in combination. The manufacturing process of the said nonwoven fabric is not specifically limited, According to the conventional method in the industry.

However, in the case of the nonwoven fabric, it is preferable that the pore size of the nonwoven fabric measured by the bubble point method is 1 to 20 µm, and more preferably 1 to 5 µm.

In addition, the step of plasma treating the surface of the nonwoven fabric is preferably carried out in a mixed gas atmosphere containing a fluorocarbon gas of 1 to 3 carbon atoms and a hydrocarbon gas of 1 to 3 carbon atoms in a volume ratio of 50:50 to 90:10. .

The conventional method related to the plasma surface treatment technology is a method of simultaneously imparting water and oil repelling performance by forming a fluorine compound having a low surface tension on the surface of a substrate using Fluorine series, that is, C ₂ F ₆ or C ₃ F ₆ gas. Mainly used. Therefore, when a specific performance of the oil / water separation function such as a fuel filter for a diesel vehicle is required, existing technologies for simultaneously providing water / oil repelling performance are not suitable.

However, the plasma coating layer of the present invention is to adjust the surface tension of the plasma coating layer by appropriately adjusting the mixing ratio of the fluorocarbon gas and hydrocarbon gas.

In the plasma surface treatment technology of the present invention, it is preferable to use a plasma surface treatment apparatus using an RF plasma source, and the plasma surface treatment apparatus includes a vacuum chamber, a gas injection apparatus, and a power generator capable of reaching a constant degree of vacuum. good.

More specifically, the plasma surface treatment step includes the steps of: i) placing the nonwoven fabric in the chamber, and then setting the initial pressure in the chamber to 20 to 30 mTorr; ii) injecting the mixed gas into a chamber; iii) stabilizing the pressure in the chamber to 50 to 150 mTorr; And iv) plasma treatment with a power of 200 to 600 W.

The oil-water separation material of the present invention having the above constitution has a contact angle to water of 120 ° or more, preferably 140 ° or more, and more preferably 150 ° or more.

In particular, the oil-water separation filter including the oil-water separation material exhibits an effect of 95% or more (@ 180 hrs) of oil-water separation performance measured according to test standard ISO 16332.

The oil and water separation material may be used as a material for liquid / liquid separation, and more preferably, may be used as an in-tank filter for a vehicle or a spin-on filter, a diaphragm material for the electric / electronics industry, and the like. It can be used as aerosol separation material for industrial machinery, and air purification material for clean room as material for liquid separation. In addition, it can be used for various industrial filters.

Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Example  One

1 minute under a mixed gas (volume ratio 90:10) of C ₂ F ₆ and CH ₄ under an initial vacuum of 20 mTorr, 300 W power using a low temperature low pressure plasma apparatus for a nylon 6 meltblown nonwoven fabric having a weight of 150 GSM. Liver plasma surface treatment. The size of the treated sample was 200 × 150 mm, the sample was placed in a tray between the electrodes, and when the initial vacuum was reached, the mixed gas was injected at a flow rate of 70 sccm, and then the plasma surface treatment was performed at a working vacuum of 100 mTorr. .

Example  2

Plasma surface treatment was carried out in the same manner as in Example 1, except that the volume ratio of the mixed gas of C ₂ F ₆ and CH ₄ was 80:20.

Example  3

Plasma surface treatment was performed in the same manner as in Example 1 except that the volume ratio of the mixed gas of C ₂ F ₆ and CH ₄ was 70:30.

Example  4

Plasma surface treatment was performed in the same manner as in Example 1 except that the volume ratio of the mixed gas of C ₂ F ₆ and CH ₄ was 60:40.

Example  5

Plasma surface treatment was performed in the same manner as in Example 1 except that the volume ratio of the mixed gas of C ₂ F ₆ and CH ₄ was 50:50.

Example  6

The nonwoven fabric of Example 2 was subjected to plasma surface treatment for 1 minute under an atmosphere of argon gas under an initial vacuum of 20 mTorr and 300 W power condition using a low temperature low pressure plasma apparatus to impart irregularities to the fiber surface, and then The plasma surface treatment was performed by the method.

Comparative example  One

100% Nylon 6 nonwoven fabric without any treatment was used as it is.

Comparative example  2

Plasma surface treatment was carried out in the same manner as in Example 1 except that C ₂ F ₆ was used alone instead of using a mixed gas of C ₂ F ₆ and CH ₄ .

The surface of the sample prepared according to Examples 1 to 6 and Comparative Example 2 was analyzed by ESCA to summarize the components of the plasma coating layer detected in Table 1 below.

TABLE 1

division Gas used Peak area F _1s / C _1s C _1s F _1s Example 1 C ₂ F ₆ + CH ₄ (9: 1) 81.47515 10.5853 0.129921 Example 2 C ₂ F ₆ + CH ₄ (8: 2) 82.43387 9.1311 0.110769 Example 3 C ₂ F ₆ + CH ₄ (7: 3) 78.29511 6.2634 0.079997 Example 4 C ₂ F ₆ + CH ₄ (6: 4) 79.67862 6.2656 0.078636 Example 5 C ₂ F ₆ + CH ₄ (5: 5) 79.61442 5.0974 0.064026 Example 6 C ₂ F ₆ + CH ₄ (8: 2) 78.31218 8.67455 0.105231 Comparative Example 1 - 82.79018 - - Comparative Example 2 C ₂ F ₆ 70.86396 16.3746 0.231071

In addition, the oil repellency of the samples prepared according to Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated according to the AATCC-118 Oil Repellency Test method, and the water repellency was evaluated according to the AATCC-22 Water Repellency Test method.

In addition, the surface tension of 25 ℃ was measured according to the Pendent Drop Method.

The evaluation results are summarized in Table 2 below.

TABLE 2

division Use gas Water repellency Oil repellent Surface tension (10 ^-2 J / m ² ) Example 1 C ₂ F ₆ + CH ₄ (9: 1) Grade 2 Grade 4 3.02 Example 2 C ₂ F ₆ + CH ₄ (8: 2) Grade 2 X 4.62 Example 3 C ₂ F ₆ + CH ₄ (7: 3) Grade 2 X 5.28 Example 4 C ₂ F ₆ + CH ₄ (6: 4) Grade 2 X 5.94 Example 5 C ₂ F ₆ + CH ₄ (5: 5) Grade 2 X 6.93 Example 6 C ₂ F ₆ + CH ₄ (8: 2) Grade 2 X 4.40 Comparative Example 1 - X X 22.0 Comparative Example 2 C ₂ F ₆ Grade 2 3 ratings 2.98

As shown in the results of Comparative Example 2 of Table 2, when the nylon 6 nonwoven fabric used as the fuel filter medium in a plasma treatment for several minutes in a C ₂ F ₆ gas atmosphere to measure the oil and oil repellency by the above evaluation method Performance level 3 or higher, water repellency grade 2 or higher.

In this case, when the nylon 6 melt-blown nonwoven fabric as in Examples 1 to 5 in the plasma treatment in the presence of a mixture gas of C ₂ F ₆ gas and CH ₄ gas, the oil repellency is less or less than two grades of water repellency without change Can be confirmed.

In addition, as shown in Example 6 to give a fine surface irregularities and then plasma treatment in the presence of a mixture gas of C ₂ F ₆ gas and CH ₄ gas, it is confirmed that excellent water repellency is expressed even if less expensive C ₂ F ₆ gas is used Can be.

In order to visually prove the effect of the present invention, the water and oil repellency test photographs after dropping water and diesel fuel on the surface of the sample prepared according to Example 2 and Comparative Example 1 are shown in Figs. 4 and 5, respectively. It was.

As shown in FIG. 4, the oil-separation material prepared according to Example 2 of the present invention selectively penetrates only diesel fuel without penetrating water, while prepared according to Comparative Example 1 as shown in FIG. 5. The sample penetrates both water and diesel fuel and therefore cannot serve as an oil separation filter.

 Oil and water separation material of the present invention is excellent in the separation of oil and water separation, excellent oil durability, can be used as a fuel filter of various automobiles and industrial machines equipped with a diesel engine, gasoline engine, etc. .

Claims (8)

An oil-separated material having a plasma coating layer having a surface tension of 3.0 × 10 ⁻² J / m ² to 7.2 × 10 ⁻² J / m ² formed on a surface of a nonwoven fabric including polymer fibers. The method of claim 1, The plasma coating layer is formed by plasma vapor deposition of a mixed gas containing fluorocarbon gas having 1 to 3 carbon atoms and hydrocarbon gas having 1 to 3 carbon atoms in a volume ratio of 50:50 to 90:10. The method of claim 1, The polymer fiber is at least one oil-separated material selected from the group consisting of polyamide fibers and polyester fibers. The method of claim 1, The polymer fiber is an oil and water separation material having an average diameter of 1 to 10㎛. The method of claim 1, The nonwoven fabric includes staple fibers, manufactured by a method such as needle punching, thermal bonding, hot air bonding, hydroentanglement, or by spunbond, meltblown, or flash spinning, which is a direct spinning method. Oil and water separation material, which is a single or composite nonwoven fabric produced. The method of claim 1, Plasma etching the surface of the nonwoven fabric prior to the plasma treatment step to form irregularities on the surface of the polymer fiber and the nonwoven fabric comprises a polymer fiber having irregularities formed on the surface. The method of claim 1, The oil-water separation material is a water-oil separation material having a contact angle of 120 ° or more. An oil-water separation filter comprising the oil-water separation material according to any one of claims 1 to 7.

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