KR20210081969A - Method for preparing sponge type liphophlic gel for absorbing and removing volatile organic compounds - Google Patents

Abstract

A lipophilic gel of the present invention exhibits sponge-like physical properties by standardizing and drying a polymer polymerized using a silicone monomer. Therefore, the lipophilic gel of the present invention, due to the silicone monomer and a large surface area, can efficiently adsorb volatile organic compounds present in fluid gas.

Description

Method for preparing a sponge-type lipophilic gel for absorbing and removing volatile organic compounds {Method for preparing sponge type liphophlic gel for absorbing and removing volatile organic compounds}

The present invention relates to a method for preparing a sponge-type lipophilic gel for absorbing and removing volatile organic compounds.

As industry develops and populations increase worldwide, emissions of various pollutants are increasing. In particular, hazardous substances such as volatile organic compounds (VOCs) are discharged into the air, soil and water system, which is a problem. . VOCs can exist in a liquid or solid state at room temperature and pressure, and refer to hydrocarbon compounds that are easily evaporated in the atmosphere due to high vapor pressure. Although some VOCs are emitted from natural environments such as soil, wetlands, and grasslands (Guenther et al., 1995), in general, relatively large amounts are emitted from organic solvent-using facilities, automobiles and industrial facilities (Yang et al., 2018). ; Zhang et al., 2017). VOCs stink after evaporation and can cause photochemical smog by causing photochemical reactions in the atmosphere (Shen et al., 2013). In addition, as a toxic substance with carcinogenicity, long-term exposure to humans causes serious effects, and when ingested in large amounts, it can cause acute and chronic poisoning, carcinogenesis, genetic mutation, and malformations (Padhi and Gokhale, 2014). In order to reduce and remove VOCs emitted from industrial facilities, studies on VOCs adsorption and chemical oxidation have been conducted. The VOCs adsorption method can remove VOCs dissolved in the atmosphere with various adsorbents for VOCs discharged from industrial facilities, but there is a disadvantage that the existing facility needs to be equipped with a condensation and separation facility and a washing and treatment facility for the adsorbed material after adsorption. (Yun and Kim, 2017; Fang et al., 2016; Dumont et al., 2012; Darracq et al., 2012). Chemical oxidation methods such as UV reactor and ion plasma process can also be used to remove VOCs present in the atmosphere, but the disadvantage is that large facilities and high energy are required to perform processes such as agglomeration and precipitation in the oxidation process. (Kang et al., 2017; Park and Jo, 2014). In addition, as a means to reduce VOCs, when VOCs are introduced from devices or facilities that include VOCs absorption processes such as condensation, storage, sedimentation, and separation, irregularly high concentrations of VOCs are introduced. This increases the occurrence of safety accidents by causing a rapid temperature rise depending on environmental conditions, and accordingly, a pretreatment damping technology that can quickly absorb high concentrations of VOCs flowing irregularly or intermittently from the VOCs treatment device is required ( Zhang et al., 2017; Muzenda, 2013). Recently, by manufacturing a material for VOC absorption and removal using hydrophobic polymer and silicone oil, it is used instead of the existing VOCs removal facility or applied to a conventional large facility to prevent excessive accumulation of VOCs in the facility. Methods for this are being studied (Montes et al., 2011; Darracq et al., 2010; Ono et al., 2007).

On the other hand, the silicone oil used in the VOCs reduction device is a liquid residue when replaced, which causes failure and accidents of the reduction device. In order to overcome this problem, the present inventors designed a lipophilic gel grafted with a silicone monomer. The invention was completed.

PCT/EP2010/005502

In the present invention

1) mixing monomer A, crosslinking agent B and acrylamide,

A is 3-(trimethoxysilyl)propyl methacrylate, methallyltrimethylsilane, allyltrimethylsilane, vinyltrimethylsilane, trimethylsilyl acrylate, trimethylsilyl methacrylate, allyloxytrimethylsilane, 2-methyl-1- (trimethylsiloxy)-1-propene, 2-(trimethylsiloxy)ethyl methacrylate, any one selected from the group consisting of allyloxy-tert-butyldimethylsilane and vinyltrimethoxysilane;

B is N,N-methylenebisacrylamide, polyethylene glycol diacrylate (poly(ethylene glycol)diacrylate), ethylene glycol diacrylate, N,N'-1,2-di Hydroxyethylene bisacrylamide (N,N′-(1,2-dihydroxyethylene)bisacrylamide), 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate rate (1,6-hexanediol diacrylate), 1,4-butanediol diacrylate (1,4-butanediol diacrylate), glycerol 1,3-diglycerolate diacrylate, Any one selected from the group consisting of diethylene glycol diacrylate (di(ethylene glycol) diacrylate), neopentyl glycol diacrylate, and polypropylene glycol diacrylate phosphorus step;

2) adding an initiator to the mixture of step 1) for polymerization;

3) normalizing the reactants of step 2);

4) supporting the product of step 3) in water; and

5) It aims to provide a method for preparing a lipophilic gel comprising the step of drying the product of step 4).

Another object of the present invention is to provide a lipophilic gel prepared by the above preparation method.

Another object of the present invention is to provide the use of the lipophilic gel.

One aspect of the present invention for achieving the above object is

1) mixing monomer A, crosslinking agent B and acrylamide,

A is 3-(trimethoxysilyl)propyl methacrylate, methallyltrimethylsilane, allyltrimethylsilane, vinyltrimethylsilane, trimethylsilyl acrylate, trimethylsilyl methacrylate, allyloxytrimethylsilane, 2-methyl-1- (trimethylsiloxy)-1-propene, 2-(trimethylsiloxy)ethyl methacrylate, any one selected from the group consisting of allyloxy-tert-butyldimethylsilane and vinyltrimethoxysilane;

B is N,N-methylenebisacrylamide, polyethylene glycol diacrylate (poly(ethylene glycol)diacrylate), ethylene glycol diacrylate, N,N'-1,2-di Hydroxyethylene bisacrylamide (N,N′-(1,2-dihydroxyethylene)bisacrylamide), 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate rate (1,6-hexanediol diacrylate), 1,4-butanediol diacrylate (1,4-butanediol diacrylate), glycerol 1,3-diglycerolate diacrylate, Any one selected from the group consisting of diethylene glycol diacrylate (di(ethylene glycol) diacrylate), neopentyl glycol diacrylate, and polypropylene glycol diacrylate phosphorus step;

2) adding an initiator to the mixture of step 1) for polymerization;

3) normalizing the reactants of step 2);

4) supporting the product of step 3) in water; and

5) To provide a method for preparing a lipophilic gel comprising the step of drying the product of step 4).

Step 1) is a step of preparing a mixed solution in a uniform state by mixing monomer A, crosslinking agent B, and acrylamide to polymerize the lipophilic gel.

The volatile organic compound referred to in this specification is considered to be a gaseous material, hereinafter referred to as a volatile organic compound, but the scope may be extended to a gaseous material.

In addition, the volatile organic compounds referred to in the present specification may be interpreted to include intermediate decomposition products or decomposition products derived from the volatile organic compounds depending on context.

The monomer A is a monomer containing silicone, and as it contains silicone, it can efficiently adsorb volatile organic compounds. In a specific embodiment, the monomer A is 3-(trimethoxysilyl)propyl methacrylate, methacrylate, methallyltrimethylsilane, allyltrimethylsilane, vinyltrimethylsilane, trimethylsilyl acrylate, trimethylsilyl methacrylate with allyloxytrimethylsilane, 2-methyl-1-(trimethylsiloxy)-1-propene, 2-(trimethylsiloxy)ethyl methacrylate, allyloxy-tert-butyldimethylsilane and vinyltrimethoxysilane It may be any one selected from the group consisting of. Preferably, the monomer A may be 3-(trimethoxysilyl)propyl methacrylate.

The crosslinking agent B serves to form crosslinks between polymer chains so that the lipophilic gel can be crosslinked. In a specific embodiment, the crosslinking agent B is N,N-methylenebisacrylamide, polyethylene glycol diacrylate, ethylene glycol diacrylate, N, N'-1,2-dihydroxyethylenebisacrylamide (N,N'-(1,2-dihydroxyethylene)bisacrylamide), 1,3-butanediol diacrylate, 1 ,6-hexanediol diacrylate (1,6-hexanediol diacrylate), 1,4-butanediol diacrylate (1,4-butanediol diacrylate), glycerol 1,3-diglycerolate diacrylate (glycerol) 1,3-diglycerolate diacrylate), diethylene glycol diacrylate (di(ethylene glycol) diacrylate), neopentyl glycol diacrylate, and polypropylene glycol diacrylate (poly(propyleneglycol) diacrylate) It may be any one selected from the group. Preferably, the crosslinking agent B may be N,N-methylenebisacrylamide.

Monomer A, crosslinking agent B, and acrylamide in step 1) may be mixed in a molar ratio of 20 to 150: 1:2. The content of silicon in the composition is determined by the molar ratio, so that the absorption capacity of the volatile organic compound of the lipophilic gel can be controlled.

In step 2), an initiator is added to the mixture to form a polymer from the mixtures as a raw material. The initiator is an initiator commonly used in polymer synthesis, for example, AIBN (Azobisisobutyronitrile), AMVN (2,2'-azobis (2,4-dimethylvaleronitrile)) and AAPH (2,2'-azobis (2-amidinopropane) ) dehydrochloride), may be.

Step 2) may be polymerization by reacting at 60 to 100° C. for 12 to 36 hours. In a specific embodiment, in step 2), polymerization is preferably performed by reacting at 70 to 80° C. for about 20 to 28 hours, preferably for about 24 hours. Such polymerization may be carried out under conventional organic solvent conditions, for example, DMSO (dimethyl sulfoxide), Heptane, Hexane, Octane, Nonane, Decane, Octanol, Dichloromethane, Diethylether, Dimethylether, Dipropylether, Dihexylether, Dibutylether, Dipentylether, It is preferable to use Dihepylether, Pyridine, Tetrahydrofuran, Acetone, Acetonitrile and DMF (Dimethylformamide).

Step 3) is a step of normalizing the polymer polymerized in step 2).

In the present invention, standardization may mean standardized molding. That is, it means cutting or molding the prepared polymer to have a predetermined thickness, width, and/or length.

In a specific embodiment, the normalization may be normalizing to a circle having a diameter of 5 to 11 mm. Preferably, it may be standardized as a circle having a diameter of 8 mm, and the thickness thereof may be 6 to 12 mm.

Step 4) is a step of substituting the organic solvent in the gel with water by supporting the polymer standardized in step 3) in water. That is, the prepared polymer uses liquid nitrogen to cool the organic solvent inside the gel, and by supporting it in water, the gel structure is maintained and the organic solvent is dissolved while the inside of the gel is replaced with water, and the inside of the gel is lyophilized through lyophilization. By removing water, it is possible to prepare a sponge-type lipophilic gel capable of adsorbing volatile organic compounds more efficiently.

Step 5) is a step of drying the product of step 4) to form a sponge-like structure. Through the drying process of step 5), the lipophilic gel has sponge-like properties and has a large surface area, so that volatile organic compounds can be efficiently adsorbed. Normal pressure drying, air stream drying, belt drying, fluidized-bed drying, freeze drying, or supercritical CO ₂ drying. Preferably, the drying may be freeze-drying. Accordingly, it is possible to better form a lipophilic gel having sponge-like physical properties.

Another aspect of the present invention for achieving the above object is to prepare a lipophilic gel prepared by the above method. The lipophilic gel prepared by the above preparation method has sponge-like properties and has a large surface area, so that it is possible to efficiently adsorb volatile organic compounds.

Specifically, the lipophilic gel according to the present invention can efficiently adsorb the silicone monomer and the volatile organic compound present in the fluid gas due to its large surface area. According to a specific embodiment of the present invention, it has the effect of adsorbing volatile organic compounds present in the flowing gas over a large surface area.

That is, the present invention provides a composition for absorbing volatile organic compounds comprising the lipophilic gel prepared by the above method.

“VOC (Volatile Organic Compounds)” refers to volatile organic compounds that can exist in a liquid or solid state at room temperature and pressure, and evaporate easily due to high vapor pressure in the atmosphere. It refers to all organic compounds that can exist in a gaseous state at room temperature and pressure conditions, such as hydrocarbons containing nitrogen or sulfur. For example, these volatile organic compounds include, but are not limited to, benzene, toluene, xylene, methyl ethyl ketone, acetone, isopropyl alcohol, glycol ether, crude oil refinery, naphtha, and the like.

The composition for absorbing volatile organic compounds according to the present invention can adsorb and block volatile organic compounds with harmful substances through excellent adsorption efficiency while having a large surface area, so automobile interior materials, furniture, restaurants, painting equipment, interior painting, laundry, printing It can be used as an absorbent material for absorbing VOCs emitted by

The present invention also provides a method for removing volatile organic compounds, comprising the step of contacting the composition for absorbing volatile organic compounds including the lipophilic gel prepared by the above method with the volatile organic compounds.

The present invention also provides a lipophilic gel comprising 3-(trimethoxysilyl)propyl methacrylate, N,N-methylenebisacrylamide and acrylamide in a molar ratio of 20 to 150:1:2.

Overlapping contents are omitted in consideration of the complexity of the present specification, and terms not defined otherwise in this specification have the meanings commonly used in the technical field to which the present invention pertains.

The lipophilic gel of the present invention exhibits sponge-like physical properties by standardizing and drying a polymer polymerized using a silicone monomer. Therefore, the lipophilic gel of the present invention can efficiently adsorb the silicone monomer and the volatile organic compound present in the fluid gas due to its large surface area.

1 is a schematic view showing the manufacturing process of the lipophilic gel according to Example 1.
2 shows (a) an image of a sponge-type lipophilic gel, (b) an image of a swollen lipophilic gel, and (c) a sponge structure of the lipophilic gel observed with a scanning cell microscope (bottom) of a sponge-type lipophilic gel. The internal structure and VOCs absorption mechanism are shown.
3 is a schematic diagram showing the experimental procedure for measuring the partition coefficient according to Example 2.
4 is a graph showing the correlation between the amount of 3-(trimethoxysilyl)propyl methacrylate and the partition coefficient.
5 is a schematic diagram showing the experimental procedure for measuring the absorption rate of volatile organic compounds in the flowing gas of the lipophilic gel.
6 shows the results of an experiment for measuring the absorption rate of volatile organic compounds in the flowing gas of the lipophilic gel for each sample.
7 is a graph showing the correlation between the absorption rate of volatile organic compounds in the flowing gas of the lipophilic gel and the amount of 3-(trimethoxysilyl)propyl methacrylate.
8 shows the absorption rate of the lipophilic gel sample B according to the toluene flow rate.

Hereinafter, preferred examples are presented to help the understanding of the present invention. However, the following examples are only provided for easier understanding of the present invention, and the content of the present invention is not limited by the examples.

Example 1. Preparation of lipophilic hydrogel

By polymerizing the silicone-incorporated monomer 3-(trimethoxysilyl)propyl methacrylate (3-(trimethoxysilyl)propyl methacrylate, MPTS) with the crosslinking agent N,N-methylenebisacrylamide (N,N-methylenebisacrylamide, MBA), A lipophilic gel for absorbing VOCs was prepared. First, the concentration of MPTS and acrylamide (acrylamide, AAm) and the concentration of MBA were adjusted for each example to prepare 50 ml of a mixed solution. Then, using DMSO (dimethyl sulfoxide) as a solvent, 0.04 M of an initiator AIBN (azobisisobutyronitrile) was added, and after heating and gelation in a 500 ml reactor at 70-80° C. for 24 hours, it was standardized in a circular shape with a punch of 8 mm in diameter. The prepared gel was loaded in distilled water to replace DMSO in the gel with distilled water, and then pores were introduced into the gel through freeze-drying to finally prepare a sponge-type lipophilic gel. A schematic diagram of a specific manufacturing process is shown in FIG. 1 .

Concentrations according to specific examples are shown in Table 1 below, and they were named samples A, B and C according to the concentrations of MPTS, AAm, MBA, and initiator AIBN, respectively.

[Table 1]

The form of the prepared lipophilic gel is shown in Fig. 2 (a), the form of the swollen lipophilic gel is shown in Fig. 2 (b), and the form of the internal structure was observed with a scanning cell microscope and shown in Fig. It is shown in (c).

Example 2. Partition coefficient measurement of lipophilic hydrogels

The standardized lipophilic gel was placed in a vial with a volume of 3 ml, and VOCs were injected at a concentration of 40,000 ppm. In this experiment, toluene was selected as a representative material of VOCs. After blocking from the external environment, gaseous toluene was saturated and stabilized at 150 rpm at room temperature for 3 hours. Finally, the amount of residual toluene in the gas phase was analyzed through GC-FID (7890A; HP-5 column, Agilent, USA) of the stabilized gas phase inside the vial to calculate the partition coefficient (P ). Partition coefficient (P) is the equilibrium VOCs concentration on the divided gas (C _G) and can be calculated as shown below in Equation 1 as VOCs concentration (C _L) on the equilibrium distributed absorber, and which VOCs absorption of the resulting lipophilic gel used as an indicator. A schematic diagram of a specific experiment is shown in FIG. 3 .

............................... 식 1

............................... Equation 1

In the same manner, the partition coefficient of the lipophilic gel was analyzed compared to that injected with only toluene at a concentration of 40,000 ppm into the vial. At this time, the concentration of VOCs in the absorbent phase distributed in equilibrium is calculated as in Equation 2 below by using the initial mass of toluene injected (M _T ), the volume of the gas phase ( V _G ), and the volume ( V _L ) of the lipophilic gel, which is the VOCs absorbent. did. For C _G , a value measured by GC-FID analysis of the stabilized gas phase after 3 hours was used.

............................... 식 2

............................... Equation 2

As shown in FIG. 4 , it was confirmed that the partition coefficient of the lipophilic gel showed the smallest value in Sample A having an MPTS concentration of 2.0 M and the highest in Sample C having a concentration of 0.6 M. These results confirm that the larger the concentration of equilibrium distributed VOCs, the smaller the partition coefficient value, and the higher the content of MPTS, a monomer containing silicone, of the lipophilic gel, the better the toluene absorption capacity of the lipophilic gel.

Example 2. Determination of Absorption Rate of Lipophilic Gels in Flowing Gas Phase

As shown in the schematic diagram of FIG. 5, the Tedler bag containing the target VOCs was connected to the glass column containing the lipophilic gel, and the VOCs of the Tedler bag were sucked by using a pump, and the absorption rate of the lipophilic gel was measured in the flowing gas phase. . The target VOCs were selected as toluene, and the gaseous toluene in the Tedler bag was stirred at 40 ° C. at 150 rpm for 15 hours after injecting liquid toluene into a 10L-Tedler bag filled with air, and then lowering the temperature to 25 ° C for 52 hours. It was prepared by stirring. The lipophilic gel was filled in a 5 ml volume in a 7 ml glass column and the amount of toluene absorbed for 30 minutes was analyzed by GC-FID. Using a suction pump (AIRWELL2010, Odortech), toluene passed through a glass column at a constant flow rate of 400 ml/min, and the amount of toluene absorbed through the difference between the area of the inlet (●) and the area of the outlet (○) was calculated and sampled. The results for each A, B, and C are shown in a, b and c of FIG. 6, respectively. In addition, the toluene concentration before and after passing through the glass column was measured by GC-FID to calculate the absorption rate of the lipophilic gel, and the results are shown in FIG. 7 for each MPTS concentration.

As a result, as the content of the silicone monomer MPTS increased, the partition coefficient tended to increase, but the absorption rate in the flowing gas was not proportional to the amount of the silicone monomer MPTS and showed the largest value at 1.4 M, which is the amount of MPTS. It shows a difference in the absorption rate between the lipophilic gel exhibiting rubber properties at a relatively high 2.0 M and the lipophilic gel having a sponge form at a relatively low 1.4 M, which is more important than the amount of MPTS. This is a result that shows that Through this, while the lipophilic gel is prepared in the form of a sponge, the absorption rate of VOCs of the lipophilic gel can be optimized according to the flow state of the gas phase.

Example 3. Measurement of absorption rate of lipophilic gel according to flowing gas flow rate

Under the same conditions as in Example 2, the flow rate of toluene was lowered to 30 ml/min to increase the contact time between toluene and the lipophilic gel. When the flow rate was 400 ml/min, the concentration of toluene was shown in Fig. 8 (a), and when the flow rate was 30 ml/min, the concentration of toluene was shown in Fig. 8 (b), and the absorption rate according to the flow rate was shown in Fig. 8 shown in (c). The absorption rate according to the MPTS content when the flow rate was 30 ml/min is shown in (d) of FIG. 8 . As a result, it was confirmed that when the flow rate of toluene was decreased, the absorption rate of the lipophilic gel was increased. Therefore, it was recognized that the absorption rate can be controlled by changing the operating conditions in the life-friendly VOCs reduction device.

In the case of MPTS 1.4 as shown in FIG. 8, when the flow rate was 30 ml/min, the absorption rate was more than 50%. In general, it was expected that the absorption rate would increase as the amount of MPTS increased, but if too much MPTS was added, it became a rubber type rather than a sponge type, and the absorption rate decreased. Therefore, it was confirmed that the sponge-type lipophilic gel of the present invention is a lipophilic gel capable of maximally increasing the absorption of VOCs compared to the conventional rubber-type gel.

As described above, the present invention has been described through examples. Those skilled in the art to which the present invention pertains will be able to understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential characteristics thereof. Therefore, it should be understood that the above-described experimental examples are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention.

Claims (13)

1) mixing monomer A, crosslinking agent B and acrylamide,
A is 3-(trimethoxysilyl)propyl methacrylate, methacrylate, methallyltrimethylsilane, allyltrimethylsilane, vinyltrimethylsilane, trimethylsilyl acrylate, trimethylsilyl methacrylate, allyloxytrimethylsilane, 2- Any one selected from the group consisting of methyl-1-(trimethylsiloxy)-1-propene, 2-(trimethylsiloxy)ethyl methacrylate, allyloxy-tert-butyldimethylsilane and vinyltrimethoxysilane;
B is N,N-methylenebisacrylamide, polyethylene glycol diacrylate (poly(ethylene glycol)diacrylate), ethylene glycol diacrylate, N,N'-1,2-di Hydroxyethylene bisacrylamide (N,N′-(1,2-dihydroxyethylene)bisacrylamide), 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate Rate (1,6-hexanediol diacrylate), 1,4-butanediol diacrylate (1,4-butanediol diacrylate), glycerol 1,3-diglycerolate diacrylate (glycerol 1,3-diglycerolate diacrylate), Any one selected from the group consisting of diethylene glycol diacrylate (di(ethylene glycol) diacrylate), neopentyl glycol diacrylate, and polypropylene glycol diacrylate phosphorus step;
2) adding an initiator to the mixture of step 1) for polymerization;
3) normalizing the reactants of step 2);
4) supporting the product of step 3) in water; and
5) A method for producing a lipophilic gel comprising the step of drying the product of step 4). The method according to claim 1, wherein the monomer A, crosslinking agent B, and acrylamide in step 1) are mixed in a molar ratio of 20 to 150: 1:2. The method of claim 1, wherein A is 3-(trimethoxysilyl)propyl methacrylate. The method of claim 1, wherein B is N,N-methylenebisacrylamide. The method of claim 1, wherein in step 2), polymerization is performed by reacting at 60 to 100° C. for 12 to 36 hours. The method of claim 1, wherein the initiator of step 2) is benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide Oxide, hydrogen peroxide, 2.2.-Azobis(2-cyanobutane), 2,2-Azobis(methylbutyronitrile), azobis(isobutyronitrile) and azobisdimethyl-valeronitrile A method for producing a lipophilic gel that is any one selected from the group consisting of. The method for producing a lipophilic gel according to claim 1, wherein the standardization in step 3) is standardized in a circular shape with a diameter of 5 to 11 mm. The method of claim 1, wherein the drying in step 5) is freeze-drying. A lipophilic gel prepared by the method of any one of claims 1 to 8. The lipophilic gel according to claim 9, wherein the lipophilic gel has a sponge structure. 10. A composition for absorbing organic compounds comprising the lipophilic gel according to claim 9. A method for removing a volatile organic compound comprising the step of contacting the composition for absorbing organic compound according to claim 11 with the volatile organic compound. A lipophilic gel comprising 3-(trimethoxysilyl)propyl methacrylate, N,N-methylenebisacrylamide and acrylamide in a molar ratio of 20 to 150:1:2.

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