KR102573830B1 - Water impermeable material and manufacturing method thereof - Google Patents

Abstract

The present invention is a silicate mineral; and a surface modifier composed of a carbonate-based polymer and a superabsorbent polymer, and a method for preparing the same.
The composition according to the present invention significantly improves swelling performance through surface modification and can maintain swelling property even under salt water conditions, and since organic bentonite contains more replaceable cations than other clays, it is sensitive to the tendency of increasing the electrical conductivity of the slurry. However, in the case of the surface-modified silicate mineral of the present invention, it is possible to provide a liner composition capable of maintaining a constant swelling property and securing waterproof performance regardless of electrical conductivity and tendency.

Description

Liner composition and its manufacturing method {WATER IMPERMEABLE MATERIAL AND MANUFACTURING METHOD THEREOF}

The present invention is a silicate mineral; and a surface modifier composed of a carbonate-based polymer and a superabsorbent polymer, and a method for preparing the same.

Pollutants leaked from waste disposal sites, such as general garbage and toxic industrial waste, reach a level that threatens the health and life of nearby residents and become a serious problem worldwide. When chemicals such as salt water and landfill leachate come into contact with soil, interactions between clay particles and contaminants occur due to the interfacial chemical properties of the soil particle-water interface, resulting in changes in permeability and stress-strain behavior of the soil. cause changes in mechanical properties. Bentonite, among clay minerals that are widely used as barrier materials, is a material with various properties such as swelling, hydration, absorption, and cleaning. The very high hydrophilicity and expansibility of bentonite depend on the mineral montmorillonite as its main component. In addition, small amounts of feldspar, plagioclase, biotite, and quartz are included as non-functional components, but the properties of bentonite are determined by montmorillonite, the main component. Depending on the predominance of ion-exchanging cations, they are distinguished as sodium or calcium forms. Sodium bentonite, the main component of which is sodium montmorillonite, which has a higher double expansive power, is mainly used for geosynthetic clay liner materials. When saturated with water, sodium bentonite expands about 12 to 15 times its original volume and has excellent properties capable of absorbing up to 5 times its own weight in water. can be dried and hydrated. This sodium bentonite was suitable for use in civil engineering fields. Bentonite may be in powder form (powder bentonite type, PBT) or granular form (granular bentonite type, GBT).

So, various waterproof products using bentonite have been produced. In the beginning, waterproof products in the form of rigid panels were produced, but in 1982, products in the form of flexible rolls began to be produced. These roll-type products are particularly easy to install and construct on civil structures, and various types of products have begun to be produced and developed. Geosynthetic clay liner materials, which are roll-type products using bentonite, are currently applied in various fields. In the environmental field, it is mainly used for the bottom of the primary and secondary water-repellent materials of solid waste landfills, and is also applied to leak prevention in liquid storage. In addition, the range of use is gradually expanding, such as being applied to the transportation field for preventing surface contamination of soil and bedrock due to vehicle accidents and the civil engineering field of dam leakage control.

However, as a result of evaluating the hydration-swellability of bentonite for various reactants, the hydration-swellability in leachate or seawater is considerably lower than that in distilled water. The situation is.

Compared to other minerals, bentonite has a unique physico-chemical property that shows high expansibility or swelling, large specific surface area, high cation exchange capacity (CEC), and high viscosity and plasticity, so it has a very high industrial utilization, while it is very popular in coastal areas. In the case of a structure constructed in the groundwater layer, since the groundwater layer contains a large amount of chloride, when a general bentonite mat for freshwater is used, the swelling performance of the bentonite mat is affected and leakage occurs.

Currently used bentonite swells in fresh water, but does not swell in seawater, so there is a need for a method for improving the swelling performance of bentonite, which does not colloid and does not expand while expanding even in salt water.

Korean Patent Registration No. 10-0540336

The present invention solves the problem of poor swelling and loss of water-blocking function in salt water conditions as well as fresh water conditions, and to provide a salt-resistant liner composition capable of maintaining waterproof performance and securing smoothness even in salt water conditions and a method for manufacturing the same do.

In order to solve the above problems, the present invention is a silicate mineral; and a surface modifier composed of a carbonate-based polymer and a superabsorbent polymer.

In addition, the present invention comprises the steps of a) mixing a surface modifier made of a carbonate-based polymer and a superabsorbent polymer with a silicate mineral; and

b) heating the mixed solution at 60 to 80° C. to modify the surface of the silicate mineral with a surface modifier;

The composition according to the present invention can significantly improve swelling performance through surface modification and can maintain swelling property even under salt water conditions, and is sensitive to the tendency of increasing electrical conductivity of slurries because organic bentonite contains more replaceable cations than other clays. However, in the case of the surface-modified silicate mineral of the present invention, it is possible to provide a liner composition capable of maintaining a constant swelling property and securing waterproof performance regardless of electrical conductivity and tendency. In particular, due to surface modification of organic materials and polymers, proper viscosity can be maintained even in salt water conditions, so that waterproof performance or swelling properties can be secured.

1 is a water-blocking mat prepared using the composition of Example 5.
2 is a water-repellent sheet prepared using the composition of Example 5.
Figure 3 shows the swelling results of Comparative Example 1.
Figure 4 shows the swelling results of Example 5.

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

The present invention is a silicate mineral; and a surface modifier composed of a carbonate-based polymer and a superabsorbent polymer.

As the silicate mineral, kaolinite, halloysite, dicite, nacrite, odylite belonging to the kaolin family of clay minerals, talc (talc) belonging to the pyrophyllite family of clay minerals, willemsite, kerolite, Pimelite, pyrophyllite (pyrophyllite), saponite belonging to the smectite family of clay minerals, hectorite, soconite, stevensite, swinholdite, montmorillonite, beidelite, nontronite, volkonscoite , trioctahedral vermiculite, dioctahedral vermiculite belonging to the vermiculite family of clay minerals, mastovite (muscovite), phlogopite (phlogopite), annite (ironite) belonging to the mica family of clay minerals, eastnite, sidelite Lophylite tetraferri iron mica, polylithionite, ceradonite, iron ceradonite, iron aluminoceradonite, aluminoceradonite, branch mica, soda mica, sericite (sericite), interlayer defect of clay minerals Illite, haerite, bramalite, and warnesite belonging to the mica family, clintonite belonging to the bromite family of clay minerals, kinoshita, hide mica, pearl mica, and clinochlorite belonging to the chlorite family of clay minerals. , chamosite, phenantite, nimite, bayriclor, donbasite, cookate, sudoite and the like. Preferably, at least one of montmorillonite and talc (talc) is used, and most preferably, among montmorillonite, Na-bentonite, Ca-bentonite, hectorite, saponite, and attapulgite , sepiolite, and vermiculite. Even more preferably, at least one selected from the group consisting of Na-bentonite, Ca-bentonite and attapulgite is used. When using a mixture of bentonite and apapulgite, mixing in a weight ratio of 1:1 to 2:1 is particularly preferable because the self-healing performance of cracks due to swelling is excellent.

Further, as the layered silicate mineral, a mixture of the above-exemplified minerals alone or in an arbitrary combination and at an arbitrary mixing ratio may be used. The silicate mineral is preferably contained in an amount of 5 to 50% by weight based on the total filler composition, in view of exhibiting good crack self-healing performance. Silicate minerals are materials with high water absorption or swelling properties or high reaction activity with water, but have a problem in that their performance is lowered in salt water.

Therefore, in the present invention, a surface modifier is added to maintain the performance of the silicate mineral, and a carbonate-based polymer and a superabsorbent polymer are provided as the surface modifier. Carbonate-based polymers include ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, diethyl carbonate, dimethyl carbonate and ethyl It is at least one selected from the group consisting of methyl carbonate (ethyl methyl carbonate).

The superabsorbent polymer (SAP) consists of polyethylene oxide, polyacrylamide, polymethylethyl cellulose, polyethylpropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose (SCMC), polyvinyl alcohol (PVA) and starch. It is one or more selected from the group. Preferably, a polymer having a high polymerization degree is used, and a superabsorbent polymer having a high polymerization degree of n = 1700 to 4000 is used.

The carbonate-based polymer is preferably added in an amount of 200 to 300 parts by weight, most preferably 300 parts by weight, based on 100 parts by weight of the silicate mineral. In addition, the superabsorbent polymer is preferably added in an amount of 10 to 100 parts by weight, most preferably 50 parts by weight, based on 100 parts by weight of the silicate mineral.

In addition, it is preferable that geofibers are further added to the composition in an amount of 5 to 10 parts by weight based on 100 parts by weight of the silicate mineral. When geofibers are mixed, the strength of the solidified soil is further improved after moisture adsorption and the anti-crack effect appears. When added in an amount of 5 parts by weight or less, the effect is difficult to expect, and when added in an amount of 10 parts by weight or more, swelling of other components may be reduced.

In addition, the present invention is a silicate mineral; and a surface modifier comprising a carbonate-based polymer and a superabsorbent polymer. It can be used as a reinforcing agent that acts as a barrier material having various water-blocking or waterproofing functions to prevent groundwater or soil contamination, such as composite mats, woven mats, waterproof mats, non-woven fabrics for civil engineering, or water-blocking sheets, as well as water-blocking mats.

In addition, the present invention comprises the steps of a) mixing a surface modifier made of a cationic carbonate-based polymer and a superabsorbent polymer with a silicate mineral; and

b) heating the mixture at 60 to 80 °C to modify the silicate mineral with a surface modifier;

The silicate minerals of step a) are a group consisting of Na-bentonite, Ca-bentonite, hectorite, saponite, attapulgite, sepiorite, and vermiculite. Any one or more selected from is preferred, and in particular, the silicate mineral is more preferably mixed with bentonite and apapulgite at a weight ratio of 1:1 to 2:1, respectively.

The carbonate-based polymer in step a) includes ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, diethyl carbonate, and dimethyl carbonate. carbonate) and ethyl methyl carbonate (ethyl methyl carbonate). At this time, the carbonate-based polymer is preferably added in an amount of 200 to 300 parts by weight based on 100 parts by weight of the silicate mineral. The superabsorbent polymer of step a) is polyethylene oxide, polyacrylamide, polymethylethyl cellulose, polyethylpropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose (SCMC), polyvinyl alcohol (PVA), and starch. It is preferably any one or more selected from the group consisting of. In this case, the superabsorbent polymer is preferably added in an amount of 10 to 100 parts by weight based on 100 parts by weight of the silicate mineral. In step a), geofibers may be additionally added in an amount of 5 to 10 parts by weight based on 100 parts by weight of the silicate mineral. When geofibers are mixed, the strength of the solidified soil is further improved after moisture adsorption and the anti-crack effect appears.

Bentonite used in geosynthetic clay liner materials has unique physico-chemical properties that show high expansibility or swelling, large specific surface area, high cation exchange capacity (CEC), and high viscosity and plasticity compared to other minerals, so it can be used for industrial purposes. Very high usability. However, in the case of structures built in coastal areas, since the groundwater layer contains a large amount of chloride, when a general bentonite mat for freshwater is used, the swelling performance of the bentonite mat is affected and leakage occurs. Therefore, currently used Bentonite, which is being used, swells in fresh water, but has a problem in that it does not swell in seawater. This is because the water quality conditions of the reaction water affect the swelling and water-blocking performance of bentonite particles, and in the case of brine, bentonite does not colloid and expands while expanding. It is necessary to improve the swelling performance of bentonite in salt water, and in the present invention, the swelling performance is improved by using a modified organic bentonite composed of a cationic polymer and a superabsorbent polymer. Since it contains a very large number of substitutable cations compared to other clays, the tendency for the electrical conductivity of the slurry to increase with the increase in the content is sensitively shown. Therefore, the swelling performance in salt water is improved by using the substitutable cations.

In addition, bentonite loses viscosity (gel) upon contact with salt and separates from each other to lose water permeability, so it is necessary to maintain proper viscosity in order to maintain waterproof performance in a salt water environment. Therefore, it is possible to improve the swelling performance in salt water by maintaining the viscosity of the bentonite organic gel and improving the cation exchange capacity (CEC) by using high polymerization degree PVA.

Therefore, it is to identify the characteristics of the surface properties of bentonite, purify the raw material bentonite through a relatively simple process, and prepare organic bentonite with improved swelling performance in salt water according to the change in electrical conductivity by using a modifier for the surface properties.

For this reason, the inventors of the present invention can modify the surface properties of bentonite and prepare a mixed soil with improved swelling property using the modified bentonite.

Hereinafter, the present invention will be described in more detail through examples. The following examples are provided to more easily understand the present invention, but the contents of the present invention are not limited by the examples.

[Examples and Comparative Examples]

Preparation of liner composition

As shown in Table 1 below, a liner composition was prepared using sodium bentonite, attapulgite, propylene carbonate, polyvinyl alcohol (PVA 1500), and sodium carboxymethyl cellulose (SCMC), and after mixing them at 60 ° C. heated for 24 hours. The unit is g, and Examples 1 to 10 and Comparative Examples 1 to 2 were prepared according to each component composition.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Na-Bentonite 10 0 10 10 10 10 10 20 20 20 20 20 attapulgite 0 10 10 10 10 10 10 10 10 10 10 10 propylene carbonate 0 0 10 20 20 60 60 15 30 30 90 90 polyvinyl alcohol 0 0 0 10 0 10 0 0 15 0 15 0 SCMC 0 0 10 0 10 0 10 10 0 15 0 15

In addition, Examples 11 to 13 were prepared by adding 1 g, 2 g, and 3 g of geofibers to Example 4, respectively.

Example 14

Manufacture of water-blocking mat

Using the compositions of Comparative Example 1 and Example 5, a PVA film and the composition of the present invention were added to a nonwoven fabric to prepare a water-blocking mat, respectively. 1 shows a mat prepared using the composition of Example 5.

Example 15

Manufacture of water barrier sheet

A water-repellent sheet was prepared by adding a PVA film and the composition of the present invention to the HDPE sheet using the compositions of Comparative Example 1 and Example 5. 2 shows a sheet prepared using the composition of Example 5. It can be applied in a variety of ways, such as pollution prevention, underground tanks, and civil engineering structures.

[Experimental Example]

Experimental Example 1: Free swell index measurement

In order to measure the degree of swelling of the compositions of Comparative Examples and Examples, 100 ml of distilled water was added to each composition, and after 24 hours, the swelling free swelling index was measured according to ASTM 5887.

The results of measuring the free expansion index of Examples 1 to 13 and Comparative Examples 1 to 2 are shown in Table 2 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 free expansion exponent 12 11 15.1 22.3 26 35 39 14 19.8 21.4 28 32

As can be seen from the table above, the Pyeongchang index was low in the case of the comparative example, and the index value was generally high in the case of the modified composition. This shows that the modification effectively increases the expansion index, and overall, the composition modified with propylene carbonate and polyvinyl alcohol or SCMC in the silicate mineral mixed with sodium bentonite and attapulgite showed a high index value. This confirms that the modification has a direct effect on the swelling behavior, and the index value shows a slight difference depending on the ratio or composition of the components. Examples 4 and 5 showed the highest values.

Experimental Example 2: Measurement of Free Swelling

In order to measure the degree of swelling of the comparative and example compositions, 100 ml of distilled water was added to each composition and the swelling volume was measured according to ASTM 5890 after 24 hours. The results are shown in Table 3 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 degree of free swelling 16 14 49 67.8 75.4 99.4 100 43.8 62.3 60.9 85.6 91.2

As can be seen from the table above, in the case of the comparative example, the swelling degree was too low, and it was confirmed that it was remarkably improved through modification. In particular, in the case of Examples 4 and 5, it was confirmed that the excellent function of the liner material could be exhibited by showing the degree of swelling close to 100. 3 shows the swelling results of Comparative Example 1, and FIG. 4 shows the results of Example 5.

Experimental Example 3: Measurement of swelling degree in distilled water and saline solution

In order to measure the swelling degree of Comparative Examples 1 and 2 and Examples 4 and 5 in distilled water and saline solution, 100 ml of distilled water was added to each composition and the swelling volume was measured according to ASTM 5890 after 24 hours. The results are shown in Table 4 below.

Comparative Example 1 Comparative Example 2 Example 4 Example 5 Distilled water 10 ml 13ml 20 ml 26ml brine 5 ml 14ml 18 ml 21ml

As can be seen from the results, the comparative example composition showed a low degree of swelling in distilled water and brine, but the compositions of Examples 4 and 5 showed high values, and in particular, it can be seen that excellent degree of swelling can be maintained even in salt water there is. It is believed that this is because the polymer modification hinders the interlayer ion exchange of multivalent ions, thereby improving the swelling property.

Experimental Example 4: Measurement of permeability coefficient

In order to measure the water barrier effect of Comparative Example 1 and Example 5, the permeability coefficient was measured under a load pressure of 10 to 400 kPa according to the ASTM D4716 method using the mat and sheet. The results are shown in Table 5.

of Comparative Example 1
order mat of Comparative Example 1
water-repellent sheet Example 5
order mat Example 5
water-repellent sheet pitching factor
(Order effect below -×10 ^{-6 m2/sec} ) 1× ^10-6 1×10 ^-12 6.3 × 10 ^-9 8.7 × 10 ^-14

As can be seen from the results, it can be confirmed that the water permeability coefficient is lower in the case of the water filter mat and sheet of Example 5 compared to Comparative Example 1, so that the water filter effect is increased. This is to confirm that the swelling property can be improved and the water order performance can be excellent.

Experimental Example 5: UV stability measurement

In order to measure the ultraviolet stability of Comparative Example 1 and Example 5, tensile strength retention before and after ultraviolet irradiation was measured by ASTM D5035 method by ASTM D4355 / D4355M method using the mat and sheet. The results are shown in Table 6.

of Comparative Example 1
order mat of Comparative Example 1
water-repellent sheet Example 5
order mat Example 5
water-repellent sheet UV stability
(Tensile strength retention rate (%)) 85 85 90 92

As can be seen from the results, it was confirmed that the mat or sheet used in the composition of the present invention had no problem in ultraviolet stability.

Although the embodiments of the present invention have been described in detail above, the present invention is capable of various modifications and variations within the scope without departing from the technical spirit of the present invention described in the claims, those skilled in the art will be self-evident.

Claims (17)

A silicate mineral in which bentonite and attapulgite are mixed in a weight ratio of 1:1 to 2:1, respectively; And a surface modifier for silicate minerals composed of a carbonate-based polymer added in an amount of 200 to 300 parts by weight based on 100 parts by weight of the silicate mineral and a superabsorbent polymer added in an amount of 10 to 100 parts by weight based on 100 parts by weight of the silicate mineral. A liner composition to do. delete delete The method of claim 1, wherein the carbonate-based polymer is ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), butylene carbonate (butylene carbonate), vinylene carbonate (vinylene carbonate), diethyl carbonate (diethylene carbonate), dimethyl Any one or more compositions selected from the group consisting of carbonate (dimethyl carbonate) and ethyl methyl carbonate (ethyl methyl carbonate). The method of claim 1, wherein the super absorbent polymer is polyethylene oxide, polyacrylamide, polymethylethyl cellulose, polyethylpropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose (SCMC), polyvinyl alcohol (PVA) And at least one composition selected from the group consisting of starch. delete delete The composition according to claim 1, wherein geofibers are further added to the composition in an amount of 5 to 10 parts by weight based on 100 parts by weight of the silicate mineral. A liner mat comprising the liner material composition according to any one of claims 1, 4, 5, and 8. a) 100 weight of a cationic carbonate-based polymer and a silicate mineral added in a ratio of 200 to 300 parts by weight based on 100 parts by weight of the silicate mineral to a silicate mineral in which bentonite and attapulgite are mixed in a weight ratio of 1: 1 to 2: 1, respectively Mixing a surface modifier made of a superabsorbent polymer added in a ratio of 10 to 100 parts by weight based on parts; and
b) heating the mixture at 60 to 80° C. to modify the silicate mineral with a surface modifier; delete delete The method of claim 10, wherein the carbonate-based polymer of step a) is ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), butylene carbonate (butylene carbonate), vinylene carbonate (vinylene carbonate), diethyl carbonate (diethylene carbonate) ), a manufacturing method of at least one selected from the group consisting of dimethyl carbonate (dimethyl carbonate) and ethyl methyl carbonate (ethyl methyl carbonate). The method of claim 10, wherein the superabsorbent polymer in step a) is polyethylene oxide, polyacrylamide, polymethylethyl cellulose, polyethylpropyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose (SCMC), polyvinyl alcohol (PVA) and a manufacturing method of at least one selected from the group consisting of starch. delete delete 11. The manufacturing method according to claim 10, wherein, in step a), geofibers are further added in an amount of 5 to 10 parts by weight based on 100 parts by weight of the silicate mineral.