JP2007313400A - Gaseous hazardous substance adsorbent and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe and inexpensive gaseous hazardous substance adsorbent that is of high performance of adsorption to a gaseous hazardous substance, particularly of high adsorptive capacity thereto, and maintains high adsorptive capacity for a long period of time and a method for manufacturing a high adsorptive capacity-gaseous hazardous substance adsorbent. <P>SOLUTION: The gaseous hazardous substance adsorbent with a functional group including a base material and a polymer thin film where a surface of the base material is modified, wherein the polymer thin film is composed of an aggregate of polymer chains bonded through a polymerization initiating group on the surface of the base material, the polymer chains are straightly extended in the direction going away from the surface of the base material and have adsorptive capacity to the gaseous hazardous substance and a method for manufacturing the same. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gaseous harmful substance adsorbent having a polymer thin film having excellent adsorption ability and lifetime and a method for producing the same.

In recent years, buildings, such as houses and offices, have been increased in density by using new building materials in order to reduce construction costs, make them more comfortable, and save energy, but problems associated with these have also surfaced. New building materials emit volatile organic compounds (VOC) such as formaldehyde, toluene and xylene into the living space, causing health problems such as sick house syndrome. In addition, when a combustion appliance is used in a highly airtight living space, the concentration of CO, CO ₂ , NO _x , SO _x, etc. becomes considerably high, which may cause health problems. To improve and solve these problems effectively, volatile organic compounds contained in the living space (VOC) and NO _X removal of gaseous harmful substances such as is essential, low cost and high efficiency Development of comprehensive air quality improvement technology is being promoted by various methods.

  As one of adsorbents for gaseous harmful substances, an ion exchange fiber synthesized by a radiation graft polymerization method has attracted attention. For example, in Patent Document 1, a woven / nonwoven fabric substrate is graft-polymerized with haloalkylstyrene such as styrene or chloromethylstyrene by a radiation graft polymerization method, and then ion exchange groups are formed on the obtained graft polymer side chain. There has been proposed a gas adsorbent obtained by introducing. The radiation graft polymerization method is a method in which a polymer substrate is irradiated with radiation to form radicals, and a polymerizable monomer is grafted to the radical portion. By using this polymerization method, various shapes can be obtained. Functional functional groups can be introduced into the molecule.

  The adsorbent thus obtained does not re-release due to desorption because it adsorbs gaseous harmful substances by chemical reaction, not physical reaction such as 1) activated carbon. 2) The functional group is not physically fixed to the base material as in the case of using a method of introducing a functional group by physically impregnating the base material with a solvent, such as acid treatment or alkali treatment, Since the functional group is fixed to the substrate by a strong chemical bond, the introduced functional group itself does not desorb. 3) Compared with the introduction of functional groups by acid treatment or alkali treatment, the capacity of functional groups per weight is large. 4) Various functional groups can be introduced according to the target substance. 5) It does not impair the characteristics of the woven fabric or nonwoven fabric material.

  However, although the capacity of functional groups per weight is larger than the method of introducing functional groups by acid / alkali treatment, it has not yet fully satisfied the performance and life as an adsorbent for gaseous harmful substances. Furthermore, because high-energy radiation (electron beams, gamma rays, etc.) is used to form radicals on the substrate surface, there are concerns about safety, and it is necessary to install a large-scale manufacturing device. The problem was that the agent would be expensive.

  In addition, an adsorbent in which a macromonomer containing a functional group capable of adsorbing a gaseous harmful substance is immobilized on a substrate by the Grafton method is used to improve the capacity of the functional group per weight. It has been reported (Patent Document 2). Since the degree of polymerization of the macromonomer of this adsorbent is about 10 to 100, the amount of the functional group per one can be simply made about 10 to 100 times that of the polymerizable monomer. However, the functional group capacity per weight of the adsorbent is only about several times that of the adsorbent grafted with the polymerizable monomer.

  This is considered because it is not efficiently grafted to the radical formed on the surface of the substrate as compared with the case where the polymerizable monomer is grafted. In the method of immobilizing the macromonomer on the base material by the Graft on method, the macromonomers are not graft-polymerized all at once, but are successively graft-polymerized. That is, since the macromonomer that was initially graft polymerized does not have a macromonomer in the adjacent portion, there is no steric repulsion between adjacent macromonomers, and the macromonomer is immobilized in a very inclined state with respect to the substrate. . Therefore, the initially grafted macromonomer becomes a steric hindrance to the macromonomer to be grafted next. That is, the radical formed on the surface of the substrate is hidden, and the macromonomer cannot be graft-polymerized in the vicinity of the initially grafted macromonomer, and the radical formed on the surface of the substrate cannot be used effectively. As a result, the surface density of the formed macromonomer becomes low.

  In addition, as with the adsorbent that grafts the polymerizable monomer, high energy radiation (electron beam, gamma ray, etc.) is used to form radicals on the surface of the substrate. Since it was necessary to provide, the produced adsorbent had the problem that it became high cost.

  On the other hand, techniques for grafting polymer chains to a substrate at high density have been studied, but recently, an unprecedented high-density polymer whose chain length and chain length distribution are controlled using surface-initiated living radical polymerization. A graft surface solid having a chain immobilized on a substrate has been reported (Patent Document 3). Living radical polymerization is radical polymerization, so it has a narrow molecular weight distribution and can be synthesized easily without using a large-scale manufacturing equipment, and it is a polymerization method attracting worldwide attention. Has advantages not found in other living polymerization systems, such as a wide range and simple and safe operation, and application in various fields is being studied.

  If polymer chains with functional groups capable of adsorbing gaseous harmful substances can be grafted with high density onto the substrate using the surface-initiated living radical polymerization method, compared to the case of polymerizing the monomers and macromonomers described above It is believed that the functional group capacity per weight can be improved by orders of magnitude.

However, the polymer thin film prepared using the surface-initiated living radical polymerization method has a very narrow gap between adjacent polymer chains, and gaseous harmful substances cannot or do not easily enter the thin film. It could not be an adsorbent with excellent performance and longevity.
Japanese Patent Publication No. 6-20554 JP-A-6-327969 Japanese Patent Laid-Open No. 11-263819

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to provide a gaseous harmful substance that has a high adsorption capacity for a gaseous harmful substance, in particular, a high adsorption capacity and maintains a high adsorption capacity over a long period of time. It is an object of the present invention to provide a material adsorbent and a method for producing a high adsorbability gaseous harmful substance adsorbent with high safety and low cost.

  The gaseous harmful substance adsorbent of the present invention comprises a base material and a polymer thin film whose surface is modified, and the polymer thin film is an aggregate of polymer chains bonded to the base material surface via a polymerization initiating group. The polymer chain extends linearly in a direction away from the surface of the base material, and includes a functional group having an adsorption ability for gaseous harmful substances.

  In the gaseous harmful substance adsorbent of the present invention, the gaseous harmful substances are VOC (volatile organic compounds), aldehydes, ammonia, hydrogen sulfide, amines, mercaptans, carbon monoxide, nitrogen oxides, sulfur oxidation. It is at least one selected from the group consisting of things. Further, the functional group capable of adsorbing gaseous harmful substances is at least selected from the group consisting of an amino group, a sulfone group, a hydroxyl group, an aldehyde group, a carboxyl group, a carbonyl group, a nitro group, a phosphonic acid group, and an ammonium group. One type.

  In the gaseous harmful substance adsorbent of the present invention, the average distance between polymer chains is preferably 0.5 to 5.0 nm.

  In the gaseous harmful substance adsorbent of the present invention, the polymerization degree of the polymer chain is preferably 10 to 10,000.

  The present invention also provides a method for producing the gaseous harmful substance adsorbent comprising at least the following steps (a) and (b).

(A) a polymerization initiating group introduction step for introducing a polymerization initiating group to the substrate surface;
(B) A base material into which the polymerization initiating group has been introduced by living radical polymerization by bringing a polymerizable monomer containing a functional group capable of adsorbing gaseous harmful substances into contact with the surface of the base material into which the polymerization initiating group has been introduced. A living radical polymerization process in which a polymer chain is formed on the surface via a polymerization initiating group.

  In the polymerization initiating group introduction step, it is preferable to introduce a non-polymerizable functional group to the substrate surface together with the polymerization initiating group.

  The introduction of the polymerization initiating group and the non-polymerizable functional group to the surface of the base material is preferably performed by immersing the base material in a solution containing a polymerization initiator and a surface density controlling agent for the polymerization initiating group.

  Moreover, it is preferable that the surface density control agent of a polymerization initiating group is a functional group that can be fixed to a substrate at one end and a non-polymerizable functional group at the other end.

  2- (4-Phenyl) ethylphosphonic acid can be suitably used as the surface density controlling agent for the polymerization initiating group.

  Since the gaseous harmful substance adsorbent of the present invention has an excellent adsorption capacity, it can maintain a high adsorption capacity over a long period of time. Such a gaseous harmful substance adsorbent of the present invention is used for adsorbing and removing gaseous harmful substances from large-scale spaces such as office buildings, factories, hospitals, nursing homes, movie theaters and general homes to small-scale spaces. It can be suitably used in a wide range. Moreover, the gaseous harmful substance adsorbent of the present invention can be applied to various fields such as an air purifier using the adsorbent as a filter.

  Furthermore, according to the method for producing a gaseous harmful substance adsorbent of the present invention, since no radiation is used and no large-scale apparatus is required, a gaseous harmful substance adsorbent having a high adsorbing ability is produced safely and at low cost. can do.

  FIG. 1 is a schematic cross-sectional view of a preferred example of a gaseous harmful substance adsorbent according to the present invention. As shown in FIG. 1, the gaseous harmful substance adsorbent of the present invention comprises a base material 101 and a polymer thin film 102 with a modified base material surface. The polymer thin film 102 has a polymerization initiating group 105 on the base material surface. It is comprised from the aggregate | assembly of the polymer chain 103 couple | bonded through. Further, the polymer chain 103 extends linearly in a direction away from the surface of the base material, and has a functional group 104 having an adsorption ability for gaseous harmful substances. The polymerization initiating group 105 is introduced by allowing a polymerization initiator to act on the substrate 101 as will be described later. The polymerization initiator and the polymerizable monomer that forms the polymer chain will be described later.

  As used herein, “gaseous harmful substance” refers to a substance that is a gas and is harmful to humans. Such substances are not particularly limited, and examples thereof include VOC (volatile organic compounds), aldehydes, ammonia, hydrogen sulfide, amines, mercaptans, carbon monoxide, nitrogen oxides, sulfur oxides, and the like. it can.

  The substrate 101 used in the present invention is not particularly limited in its type, and may be any material that can introduce a polymerization initiator group 105 by allowing a polymerization initiator to act on its surface. Good. Examples of such a material include organic materials such as silicon resin, cellulose, polyolefin, polyacrylonitrile, polyester, polyamide and activated carbon, and inorganic materials such as silica, alumina and zeolite.

  Further, the shape of the base material 101 is not particularly limited, and for example, it is generally used such as a honeycomb shape, a powder shape, a spherical shape, a granular shape, a foam shape, a fiber shape, a cloth shape, or a ring shape. The shape can be used.

  The polymer chain 103 extends linearly in a direction away from the substrate surface. Here, in this specification, the “direction away from the substrate surface” does not mean that the polymer chains are all directed in the same direction, and the polymer chains are respectively directed to the substrate surface. In this way, each polymer chain has various angles, but extends in a direction approximately perpendicular to the substrate surface. That means. Further, in the present specification, the term “linear” does not mean a completely straight line, but means a state of extending straight in a certain direction and not being a random coil. Is. Thus, it can be confirmed by cross-sectional TEM observation or the like that the polymer chain 103 extends linearly in a direction away from the substrate surface.

  In order to make the polymer chain 103 linear instead of random coil, the polymerization method and the interval between adjacent polymer chains are important. As a polymerization method, living radical polymerization is suitably used as described later.

  In the present invention, the average interval between the polymer chains 103 is preferably 0.5 nm to 5.0 nm. Since the gap between the adjacent polymer chains 103 is the average distance between the polymer chains 103 minus the molecular diameter of the polymer chains, in order for gaseous harmful substances to be adsorbed to enter the polymer film, The average distance between the polymer chains 103 needs to be larger than the critical molecular diameter of the polymer chain + the critical molecular diameter of the gaseous harmful substance. When the average distance between the polymer chains 103 is less than 0.5 nm, the density of the polymer chains 103 increases, but the gaseous harmful substance cannot enter the polymer film or does not easily enter the polymer film. There is a possibility that the function cannot be performed. For example, the critical molecular diameter of formaldehyde, which is an example of a gaseous harmful substance, is 0.5 nm, the critical molecular diameter of toluene is 0.67 nm, and the critical molecular diameter of ammonia is 0.36 nm. In addition, when the interval is larger than 5.0 nm, not only the density of the polymer chain 103 decreases, but also the growth in the three-dimensional direction (direction perpendicular to the surface of the substrate 101) becomes poor, and the adsorption capacity. There is a risk of lowering. This is because, in the living radical polymerization suitably used in the present invention, the steric repulsion between adjacent polymer chains is utilized to promote the growth in the three-dimensional direction instead of the two-dimensional direction. This is because, when the interval between them is very large, the degree of conformation regulation by the polymer chains is weakened, and as a result, it approaches a random coil shape and is considered to hinder growth in the three-dimensional direction.

  In the present invention, the degree of polymerization of the polymer chain 103 is not particularly limited, but is preferably 10 to 10,000. When the degree of polymerization is less than 10, the adsorption capacity is extremely low. By increasing the degree of polymerization, the number of functional groups capable of adsorbing gaseous harmful substances can be increased, so that the adsorption capacity can be increased. The degree of polymerization of the polymer chain 103 can be set to an arbitrary value by controlling the polymerization conditions. In addition, a polymer chain is cut out by HF hydrolysis treatment, and the molecular weight and molecular weight distribution of the polymer chain are determined by using a GPC (Gel Permeation Chromatography) apparatus (for example, GPC system manufactured by Shimadzu). From the molecular weight of the obtained polymer chain The degree of polymerization of the polymer chain can be calculated.

  By adopting the above configuration, not only the density of the functional group having the ability to adsorb gaseous harmful substances in the two-dimensional direction (base material surface direction) is high, but also the three-dimensional direction (direction perpendicular to the substrate surface). ) Can also increase the number of functional groups, thereby realizing a gaseous harmful substance adsorbent with an extremely large adsorption capacity. The number of functional groups possessed by the gaseous harmful substance adsorbent of the present invention is the conventional surface for introducing functional groups such as acid / alkali solution treatment method, radiation graft monomer polymerization method, radiation graft macromonomer polymerization method, etc. This is much more than the modification method. Moreover, since the adsorption capacity is high, a high adsorption capacity can be maintained for a long time.

  The present invention also provides a method for producing the gaseous harmful substance adsorbent. As described above, controlling the distance between the polymer chains is an important factor for improving the adsorption capacity. Therefore, the present inventor has conducted extensive research on a method for controlling the interval between polymer chains. As a result, in the step of introducing the polymerization initiating group, together with the polymerization initiating group, a non-polymerizable functional group is introduced by using the surface density controlling agent of the polymerization initiating group, and the amount of the surface initiating group surface density controlling agent added It was found that the surface density of the polymerization initiating group can be controlled, and that the surface density of the polymerization initiating group and the density of the polymer chain that undergoes living radical polymerization via the polymerization initiating group show a very good correlation. . That is, it has been found that the spacing between adjacent polymer chains can be controlled by the addition amount of the surface density controlling agent for the polymerization initiating group.

The method for producing the gaseous harmful substance adsorbent of the present invention is based on the above research results. That is, the production method of the present invention comprises at least the following steps:
(A) a polymerization initiating group introduction step for introducing a polymerization initiating group to the substrate surface;
(B) A base material into which the polymerization initiating group has been introduced by living radical polymerization by bringing a polymerizable monomer containing a functional group capable of adsorbing gaseous harmful substances into contact with the surface of the base material into which the polymerization initiating group has been introduced. It includes a living radical polymerization step for forming a polymer chain on the surface via a polymerization initiating group.

  Here, in the polymerization initiating group introduction step (a), it is preferable to introduce a non-polymerizable functional group to the substrate surface together with the polymerization initiating group, and preferably a polymerization initiator and a surface density controlling agent for the polymerization initiating group are added. It is carried out by immersing the substrate in the solution containing it. As the surface density controlling agent for the polymerization initiating group, a compound in which one end is a functional group that can be immobilized on a substrate and the other end is a non-polymerizable functional group is preferably used. An example of such is 2- (4-phenyl) ethylphosphonic acid. Hereinafter, a preferred embodiment of the method for producing a gaseous harmful substance adsorbent of the present invention will be described in detail with reference to FIGS.

  In this embodiment, first, when introducing a polymerization initiating group on the surface of a substrate, a polymerization initiator is dissolved in an appropriate solvent to prepare a polymerization initiating group introduction solution. It is preferable that a surface density controlling agent for the polymerization initiating group is further dissolved in the polymerization initiating group introduction solution. By adding a surface density controlling agent for the polymerization initiating group, it is possible to control the surface density of the polymerization initiating group, and thus it is possible to control the spacing between the polymer chains.

  Here, as a polymerization initiator, a conventionally well-known thing can be used, for example, it represents with following General formula (1)-(6).

_{(1) W- (CH 2)} p -Z- (CH 2) q -SiCl n X 3-n
_{(2) W- (CH 2)} p -Z- (CH 2) q -Si (OR) n X 3-n
_{(3) W- (CH 2)} p -Z- (CH 2) q -PO 3 H 2
_{(4) W- (CH 2)} p -Z- (CH 2) q -COOH
_{(5) W- (CH 2)} p -Z- (CH 2) q -NO 2 H 2
_{(6) W- (CH 2)} p -Z- (CH 2) q -SH
The substituents and variables in the general formulas (1) to (6) will be described. Examples of W include the following structures, and include a polymerization initiating group. However, it is not limited to these.

Z represents —CH ₂ —, alkenylene, alkynylene, phenylene, aminophenylene, alkylphenylene, phenylene vinylene, phenylene ethynylene, pyridinylene, pyridyl vinylene, pyridylethynyl, thienylene, pyronylene, acene (ie, condensed polycyclic) skeleton, And pyridinopyridinylene. X is a lower alkyl group, and —CH ₃ or —C ₂ H ₅ is particularly preferred. R is —H or a lower alkyl group, and examples thereof include —CH ₃ . n is an integer of 1 to 3. p and q are integers that do not include a negative value, and p + q = 2 to 30 is most easy to handle and is preferable.

  The polymerization initiator used in the present invention is preferably formed of a linear organic molecule having a polymerization initiating group at one end and a functional group that directly chemisorbs to the surface of the substrate at the other end. Although the density | concentration of a polymerization initiator is not specifically limited, For example, it can be set as 0.002 mM-5 mM.

  As the surface density controlling agent for the polymerization initiating group, a compound in which one end of the molecule is a functional group that can be immobilized on a substrate and the other end is a non-polymerizable functional group is preferably used. Examples of the surface density control agent for the polymerization initiating group in which one end is a functional group that can be immobilized on a substrate and the other end is a non-polymerizable functional group include those conventionally known. These are represented by general formulas (7) to (12).

_{(7) V- (CH 2)} p -Z- (CH 2) q -SiCl n X 3-n
_{(8) V- (CH 2)} p -Z- (CH 2) q -Si (OR) n X 3-n
_{(9) V- (CH 2)} p -Z- (CH 2) q -PO 3 H 2
_{(10) V- (CH 2)} p -Z- (CH 2) q -COOH
_{(11) V- (CH 2)} p -Z- (CH 2) q -NO 2 H 2
_{(12) V- (CH 2)} p -Z- (CH 2) q -SH
The substituents and variables in the general formulas (7) to (12) will be described. Examples of V include the following structures, and include a non-polymerizable functional group. Any non-polymerizable functional group may be used, and the present invention is not limited to these.

Z represents —CH ₂ —, alkenylene, alkynylene, phenylene, aminophenylene, alkylphenylene, phenylene vinylene, phenylene ethynylene, pyridinylene, pyridyl vinylene, pyridylethynyl, thienylene, pyronylene, acene (ie, condensed polycyclic) skeleton, And pyridinopyridinylene. X is a lower alkyl group, and —CH ₃ or —C ₂ H ₅ is particularly preferred. R is —H or a lower alkyl group, and examples thereof include —CH ₃ . n is an integer of 1 to 3. p and q are integers that do not include a negative value, and p + q = 2 to 30 is most easy to handle and is preferable.

  The surface density controlling agent used in the present invention is preferably formed of a linear organic molecule having a non-polymerizable functional group at one end and a functional group directly chemisorbed on the surface of the substrate at the other end. Although the density | concentration of the surface density control agent of a polymerization initiating group is not specifically limited, For example, it can be set as 0.002 mM-5 mM.

  Here, in the present specification, the “surface density control agent of the polymerization initiator group” is immobilized on the surface of the base material in the same manner as the polymerization initiator, but has the property of not being graft-polymerized through this, By this property, it means an agent capable of changing the surface density of the polymerization initiating group, and the “surface density of the polymerization initiating group” is defined as the number of polymerization initiating groups per certain surface area. The “surface density of the polymerization initiating group” can be measured by high sensitivity reflection infrared spectroscopy or the like.

  The surface density of the polymerization initiating group decreases as the ratio of the addition amount of the surface density controlling agent for the polymerization initiating group to the polymerization initiator increases. Therefore, in consideration of the relationship between the surface density of the polymerization initiating group obtained for each combination of the base material to be used, the polymerization initiator, and the surface density controlling agent for the polymerization initiating group and the addition amount, the surface density of the desired polymerization initiating group is adjusted. As appropriate, the addition amount of the surface density control agent for the polymerization initiating group is adjusted. By adjusting the addition amount of the surface density control agent for the polymerization initiating group to set the surface density of the polymerization initiating group to a desired value, the interval between the polymer chains can be set to a desired value.

  In addition, in the surface density control agent of a polymerization initiating group in which one end of the molecule is a functional group that can be immobilized on a base material and the other end is a non-polymerizable functional group, the functional group that can be immobilized on the base material is a polymer It is preferably the same as the functional group that can be immobilized on the base material of the initiator. The molecular structure other than the non-polymerizable functional group is preferably the same or similar to the corresponding part of the polymerization initiator. This is because each molecule does not have a domain structure (phase separation), and both molecules can be in contact with the substrate in a substantially uniformly dispersed state.

  The solvent for dissolving the polymerization initiator and the surface density controlling agent for the polymerization initiator group is not particularly limited as long as both agents can be dissolved. For example, water, methanol, ethanol, propanol, 2-propanol, acetone, 2 -Butanone and mixtures thereof, hexane, decane, hexadecane, benzene, toluene, xylene, carbon tetrachloride, chloroform, methylene chloride, 1,1,2-trichloroethane, diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane and A mixture of these can be mentioned.

  Next, a polymerization initiating group is introduced onto the surface of the substrate using the above polymerization initiating group introduction solution (step (a)). When the polymerization initiator group introduction solution contains a polymerization initiator group surface density controller, a non-polymerizable functional group is also introduced together with the polymerization initiator group.

  FIG. 2 is a schematic cross-sectional view of a substrate having a polymerization initiating group and a non-polymerizable functional group introduced on the surface. The polymerization initiator 204 and the polymerization initiator surface density controller 207 are bonded to the substrate 201 via functional groups 202 and 205 that can be immobilized on the substrate, respectively. Thereby, the polymerization initiating group 203 and the non-polymerizable functional group 206 are introduced on the surface of the base material 201. In FIG. 2, the polymerization initiating group 203 and the non-polymerizable functional group 206 are introduced at a ratio of 1: 1, but of course the present invention is not limited to this, and the ratio can be arbitrarily set by adjusting the addition amount. Can be a value.

  As a method for introducing a polymerization initiating group and a non-polymerizable functional group onto a substrate surface using a polymerization initiating group introduction solution, a conventionally known method can be used. For example, a self-organized chemical adsorption method, Langmuir- Examples thereof include a blow jet method (LB method). These methods are very excellent because they do not require a large-scale apparatus as compared with the radiation radical forming method, can be carried out simply and safely, and do not damage the substrate. In the case of the self-organized chemisorption method in which the base material is immersed in the polymerization initiator group introduction solution, conventionally known means can be applied, and the immersion time is not particularly limited, but the treatment is longer when the temperature is low. Since time is required and the treatment is completed in a short time when the temperature is high, a range of 1 minute to 1 day is generally preferable, and a range of 5 minutes to 5 hours is particularly preferable. Moreover, although the temperature at the time of immersion does not have a restriction | limiting in particular, The range of -10-100 degreeC is preferable and the range of 0-50 degreeC is especially preferable. Also, conventionally known means can be applied to the Langmuir-Blodgett method (LB method).

  Thus, although the polymerization initiating group and the non-polymerizable functional group are introduced on the surface of the substrate, the film formed of the resulting polymerization initiating group and the non-polymerizable functional group is as shown in FIG. A monomolecular film is preferable. The formation of the monomolecular film can be confirmed with an AFM (Atomic Force Microscope) apparatus or the like.

  In addition, before introducing the polymerization initiating group into the base material, for example, when using a silicon resin as the base material, the base material is subjected to nitric acid treatment to oxidize the surface for the purpose of improving the hydroxyl group density on the surface. A process may be provided. In addition, after the substrate is immersed in the polymerization initiator introduction solution, the step of washing the substrate with a solvent and the substrate for the purpose of removing the excess polymerization initiator attached to the surface and the surface density controller of the polymerization initiator In order to dry the material, a process of blowing with Ar gas or the like may be provided. Although there is no restriction | limiting in particular in the solvent used for washing | cleaning, It is preferable that it is the same as the solvent used for preparation of the polymerization initiator group introduction | transduction solution.

  In the subsequent step, the surface of the substrate into which the polymerization initiating group has been introduced is brought into contact with a polymerizable monomer containing a functional group capable of adsorbing a gaseous harmful substance, and the polymerization initiating group is introduced by living radical polymerization. A polymer chain is formed on the surface of the material via a polymerization initiating group (step (b)). Here, in the step (a), when a non-polymerizable functional group is introduced to the substrate surface together with the polymerization initiating group, the polymer chain is grafted through the polymerization initiating group, and the non-polymerizable functional group is Since it is non-polymerizable, the polymer chain is not grafted through it.

  FIG. 3 is a schematic cross-sectional view of a gaseous harmful substance adsorbent produced according to a preferred embodiment of the production method of the present invention. In FIG. 3, a polymerization initiating group 306 and a non-polymerizable functional group 309 are introduced on the surface of the substrate 301, and the polymer chain 303 is grafted only through the polymerization initiating group 306. By introducing the non-polymerizable functional group 309 by using the surface density control agent 310 for the polymerization initiating group, it is possible to control the surface density of the polymerization initiating group and thus to control the spacing between the polymer chains 303. . That is, since the polymer chain 303 is not grafted to the non-polymerizable functional group 309, when the density of the non-polymerizable functional group 309 increases, the surface density of the polymerization initiating group decreases and the spacing between the polymer chains 303 increases. On the contrary, when the density of the non-polymerizable functional group 309 is decreased, the surface density of the polymerization initiating group is increased, and the interval between the polymer chains 303 is narrowed. Thus, by controlling the distance between the polymer chains 303 and selecting an appropriate polymerization method, the polymer chains 303 can be linearly extended in the direction away from the substrate surface. In the present invention, a living radical polymerization method is used as such an appropriate polymerization method.

  In living radical polymerization, all polymer chains grow almost uniformly, so that the steric hindrance between adjacent polymer chains is reduced and formed linearly in a direction away from the substrate surface. The conventional polymerization method grows in a random coil shape and cannot grow in a straight line shape.

  Grafting of the polymer chain 303 by the living radical polymerization method can be performed by a conventionally known means. Conventional living radical polymerization methods include, for example, nitroxyl living radical polymerization based on dissociation-bonding mechanism, atom transfer radical polymerization based on halogen atom transfer catalyzed by fiber metal complex, and reversible based on exchange chain transfer mechanism. Addition-cleavage chain transfer polymerization and the like can be mentioned. The polymerization conditions are appropriately selected according to the type of the polymerizable monomer 311 constituting the polymer chain 303, the type of the polymerization initiating group 307, the type of the surface density controlling agent 310 for the polymerization initiating group, and the like. Typically, the polymerization is carried out by immersing the substrate after the step (a) in a solution containing a polymerizable monomer and heating. For example, the polymerization temperature can be about 15 to 200 ° C., and the polymerization temperature can be 5 to 120 minutes. The solution containing the polymerizable monomer may be appropriately mixed with a catalyst and other additives for promoting the polymerization reaction.

  In the present invention, the polymerizable monomer 311 used for forming a polymer chain by living radical polymerization is a living radical polymerizable monomer having a functional group 304 capable of adsorbing a gaseous harmful substance.

  Such a living radical polymerizable monomer is not particularly limited as long as it has a functional group 304 capable of adsorbing gaseous harmful substances. For example, acrylic acid, methacrylic acid, styrene sulfonic acid, vinyl sulfone can be used. Acid, allyl sulfonic acid, methallyl sulfonic acid, methallyloxybenzene sulfonic acid, sulfoethyl methacrylate, sulfobutyl methacrylate, vinyl benzyl sulfonic acid, sodium methallyl sulfonate, sodium allyl sulfonate, vinyl benzyl trimethyl ammonium chloride, diethylaminoethyl Methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminomethyl methacrylate, tertiary butyl aminoethyl acrylate, tertiary buty Aminoethyl methacrylate, dimethylaminopropylacrylamide, acrylamide, methacrylamide, dimethylaminopropylacrylamide, dimethylacrylamide, acrylamidemethylpropanesulfonic acid, vinyl carboxylic acid, styrene carboxylic acid, allyl carboxylic acid, vinyl phosphonic acid, allyl phosphonic acid, vinyl hydroxy Alkoxy, allyl hydroxycarboxylate, acrylic aldehyde, allyl aldehyde, styrene ammonium, acrylic nitro and the like can be used. By using such a polymerizable monomer, the polarities such as functional groups of these: amino group, sulfone group, hydroxyl group, aldehyde group, carboxyl group, carbonyl group, nitro group, phosphonic acid group, ammonium group are utilized. It can effectively adsorb gaseous harmful substances such as VOC (volatile organic compounds), aldehydes, ammonia, hydrogen sulfide, amines, mercaptans, carbon monoxide, nitrogen oxides, sulfur oxides, etc. It becomes.

  As the solvent used in the living radical polymerization reaction, a solvent that is a good solvent for the polymer chain to be generated and has a small chain transfer constant is preferable, and examples thereof include water, methanol, diphenyl ether, tetrahydrofuran, benzene, toluene, and xylene.

  The degree of polymerization of the polymer chain grafted by living radical polymerization can be controlled by the polymerization time, and can be any value between 10 and 10,000. By increasing the degree of polymerization, the number of functional groups having adsorption ability also increases.

  According to the method of the present invention as described above, a gaseous harmful substance adsorbent having an extremely high adsorption capacity can be produced. The feature of the method for producing the gaseous harmful substance adsorbent of the present invention is that the interval between the polymer chains can be set to an arbitrary value depending on the size of the gaseous harmful substance to be adsorbed. This is as described above. The distance between the polymer chains can be controlled by adjusting the amount of the surface density control agent for the polymerization initiating group.

  Hereinafter, the present invention will be described in more detail based on examples. However, the materials used in the examples and their amounts, numerical conditions such as processing temperature and processing time are only examples, and these examples are used. The present invention is not limited.

<Example 1>
[Production of Gaseous Hazardous Substance Adsorbent of the Present Invention]
Using 2- (4-chlorosulfonylphenyl) ethylphosphonic acid as the polymerization initiator, 2- (4-phenyl) ethylphosphonic acid as the surface density controller for the polymerization initiator group, and ethanol as the solvent, the concentration of the polymerization initiator is 1 mM. The concentration of the surface density control agent of the polymerization initiating group is 0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, 3.0, 4.0, 5.0 mM, respectively. Then, a polymerization initiating group introduction solution was prepared. Next, a silicon substrate (size: 2 × 2 cm, thickness: 500 μm) that has been previously oxidized with nitric acid for the purpose of improving the hydroxyl group density on the surface of the base material is immersed in the polymerization initiation group introduction solution, Hold at 25 ° C. for about 1 hour. Thereafter, the substrate is washed with ethanol to remove the excess polymerization initiator and the surface density control agent of the polymerization initiator group adhering to the surface, and then sufficiently dried by Ar gas blowing to form a polymerization initiator group on the silicon substrate surface. And non-polymerizable functional groups were introduced as monolayers. Then, under vacuum deaeration, dimethylaminoethyl methacrylate (10 mM) and 4-toluenesulfonyl chloride ( 2.5 mM) is added to prepare a polymer thin film preparation solution, and the substrate into which the above-described polymerization initiating group and non-polymerizable functional group are introduced is immersed at 25 ° C., and heated to 80 ° C. after deaeration and sealing. Then, by holding for 1 to 10 hours, graft polymerization by a living radical polymerization method was performed to obtain the gaseous harmful substance adsorbent of the present invention.

[Evaluation of physical properties of the produced gaseous harmful substance adsorbent]
(Monomolecular film formation and film thickness)
Confirmation that a polymerization initiating group and a non-polymerizable functional group are introduced as a monomolecular film on the surface of a silicon substrate and measurement of the film thickness of the monomolecular film are performed by an AFM (Atomic Force Microscope) apparatus (Digital Instruments). Nanoscope III). Specifically, by observing the surface shape change (depending on the immersion time) of the silicon substrate until the monomolecular film reaches Full-Coverage, the monomolecular film grows in islands, and the monomolecular film is completely It can be seen that the silicon substrate surface is completely covered. Moreover, in the AFM image observed in a state where the full-coverage is not reached, the film thickness of the monomolecular film can be measured by measuring the step between the monomolecular film surface and the silicon substrate surface. From the measurement result, it was confirmed that it was a monomolecular film, and the film thickness was 4 mm.

(Surface density of polymerization initiating group)
The surface density of the polymerization initiation group of the monomolecular film was calculated from the symmetric stretch peak area ratio of SO ₂ or the asymmetric stretch peak area ratio of SO ₂ using FT-IR measurement (manufactured by Nicolet). FIG. 4 shows the relationship between the addition amount (mM) of the polymerization start group surface density control agent and the polymerization start group surface density (number / nm ² ) of the monomolecular film. With the increase of the addition amount of the surface density control agent 2- (4-phenyl) ethylphosphonic acid of the polymerization initiating group, the surface density of the polymerization initiating group of the formed monomolecular film is decreased, and the surface density of the polymerization initiating group It can be seen that the surface density of the polymerization initiating group can be controlled by adjusting the addition amount of the control agent.

(Dry film thickness of polymer thin film)
The dry film thickness of the formed polymer thin film was measured from a cross-sectional TEM image by performing cross-sectional observation using a TEM (Transmission Electron Microscope) apparatus (TECNAI manufactured by FEI, Japan). FIG. 5 shows the relationship between the polymerization reaction time (referred to as retention time after heating) and the film thickness of the polymer thin film when the amount of the surface density controlling agent added to the polymerization initiating group is 0.2 mM. The film thickness increases almost proportionally with increasing polymerization reaction time, and the amount of functional groups in the three-dimensional direction (direction perpendicular to the substrate surface) can be increased by increasing the polymerization reaction time. I understand. Further, by performing high-resolution TEM observation, it was confirmed that the polymer chain of the gaseous harmful substance adsorbent of the present invention was not in the form of a random coil but extended linearly.

(Molecular weight of polymer chain, molecular weight distribution and degree of polymerization)
The molecular weight and molecular weight distribution of the polymer chain were measured according to the following procedure. That is, a polymer chain was cut out by HF hydrolysis treatment, and the molecular weight and molecular weight distribution of the polymer chain were determined using a GPC apparatus (Shimadzu GPC system). Further, the degree of polymerization of the polymer chain was calculated from the molecular weight of the obtained polymer chain. FIG. 6 shows the relationship between the polymerization reaction time (referred to as the retention time after heating) and the degree of polymerization of the polymer chain in the case where the addition amount of the surface density controlling agent for the polymerization initiating group is 0.2 mM.

(Spacing between adjacent polymer chains)
The distance between the polymer chains constituting the polymer thin film was calculated from the relationship between the dry film thickness of the polymer thin film and the molecular weight of the polymer chain. FIG. 7 shows the relationship between the addition amount of the surface density controlling agent for the polymerization initiating group and the average distance between adjacent polymer chains when the polymerization reaction time during polymerization is 5 hours. By increasing the amount of addition of the surface density control agent for the polymerization initiating group, the interval between the polymer chains constituting the polymer thin film formed becomes wider, and by adjusting the amount of addition of the surface density control agent for the polymerization initiating group It can be seen that the spacing between the polymer chains can be controlled.

[Evaluation of adsorptive capacity of produced gaseous hazardous substance adsorbent]
The adsorption capacity of the gaseous harmful substance adsorbent of the present invention (using a polymerization reaction time of 5 hours) obtained as described above was continuously measured in a one-pass test using formaldehyde gas as the gaseous harmful substance. Evaluated by performing. Table 1 shows the relationship between the addition amount (mM) of the polymerization initiating group surface density control agent and the total formaldehyde adsorption capacity (mmol / g). A commercially available activated carbon for deodorization was also evaluated as a comparative product.

  It can be seen that all the adsorbents of the present invention have a very high formaldehyde total adsorption capacity as compared with commercially available deodorized activated carbon, except when the polymerization initiator surface density control agent is not added. In particular, a gaseous harmful substance adsorbent having an addition amount of the surface density control agent of the polymerization initiator group of 0.4 mM has a formaldehyde total adsorption capacity of about 4000 times that of commercially available activated carbon for deodorization, and has a removal capability. It can be seen that it is orders of magnitude higher. The reason why the formaldehyde could not be adsorbed at all without adding the surface density controlling agent for the polymerization initiating group is considered to be that the interval between adjacent polymer chains is so narrow that formaldehyde cannot penetrate into the polymer thin film. The adsorbent in which the addition amount of the surface density control agent for the polymerization initiating group is 0.2 mM has a smaller total formaldehyde adsorption capacity compared to 0.4 mM despite the high polymer chain density. Similarly, it is considered that the interval between adjacent polymer chains is narrow and formaldehyde is less likely to enter the polymer thin film.

  As described above, it is possible to control the interval between polymer chains by adjusting the addition amount of the surface density control agent of the polymerization initiating group, and it is not possible by controlling the interval between polymer chains. It is possible to realize a gaseous harmful substance adsorbent with extremely excellent adsorption capacity, particularly adsorption capacity. Since the gaseous harmful substance adsorbent of the present invention has an extremely large adsorption capacity, it can maintain a high adsorption capacity over a long period of time. Further, according to the method for producing a gaseous harmful substance adsorbent of the present invention, the interval between the polymer chains can be set to an arbitrary value according to the size of the gaseous harmful substance to be adsorbed. It can cope with gaseous harmful substances.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic sectional drawing of the gaseous harmful substance adsorption agent of a preferable example of this invention. It is a schematic sectional drawing of the base material with which the polymerization initiation group and the non-polymerizable functional group were introduce | transduced on the surface. It is a schematic sectional drawing of the gaseous harmful-substance adsorbent manufactured according to preferable embodiment of the manufacturing method of this invention. 3 is a graph showing the relationship between the addition amount of the polymerization start group surface density control agent and the polymerization start group surface density of the monomolecular film in Example 1. FIG. 2 is a graph showing the relationship between the polymerization reaction time and the film thickness of a polymer thin film in Example 1. 2 is a graph showing the relationship between the polymerization reaction time and the degree of polymerization of polymer chains in Example 1. FIG. 4 is a graph showing the relationship between the addition amount of the surface density control agent for the polymerization initiating group and the average distance between adjacent polymer chains in Example 1. FIG.

Explanation of symbols

  101, 201, 301 Substrate, 102, 302 Polymer thin film, 103, 303 Polymer chain, 104, 304 Functional group capable of adsorbing to gaseous harmful substances, 105, 203, 306 Polymerization initiation group, 202, 205, 305, 308 Functional group that can be immobilized on a substrate, 204,307 polymerization initiator, 206,309 Non-polymerizable functional group, 207,310 Surface density controller for polymerization initiator group, 311 polymerizable monomer.

Claims (10)

It consists of a base material and a polymer thin film with a modified base material surface.
The polymer thin film is composed of an assembly of polymer chains bonded to the substrate surface via a polymerization initiating group,
The polymer chain extends linearly in a direction away from the substrate surface,
The above-mentioned polymer chain is a gaseous harmful substance adsorbent containing a functional group capable of adsorbing gaseous harmful substances.   The gaseous harmful substance is at least one selected from the group consisting of VOC (volatile organic compounds), aldehydes, ammonia, hydrogen sulfide, amines, mercaptans, carbon monoxide, nitrogen oxides and sulfur oxides. The gaseous hazardous substance adsorbent according to claim 1, wherein   The functional group capable of adsorbing gaseous harmful substances is at least one selected from the group consisting of an amino group, a sulfone group, a hydroxyl group, an aldehyde group, a carboxyl group, a carbonyl group, a nitro group, a phosphonic acid group, and an ammonium group. The gaseous harmful substance adsorbent according to claim 1 or 2, wherein   The gaseous harmful substance adsorbent according to any one of claims 1 to 3, wherein an average interval between the polymer chains is 0.5 to 5.0 nm.   The gaseous harmful substance adsorbent according to any one of claims 1 to 4, wherein the polymerization degree of the polymer chain is 10 to 10,000. at least,
(A) a polymerization initiating group introduction step for introducing a polymerization initiating group to the substrate surface;
(B) A base material into which the polymerization initiating group has been introduced by living radical polymerization by bringing a polymerizable monomer containing a functional group capable of adsorbing gaseous harmful substances into contact with the surface of the base material into which the polymerization initiating group has been introduced. A living radical polymerization step for forming a polymer chain on the surface via a polymerization initiating group;
including,
The manufacturing method of the gaseous harmful | toxic substance adsorption agent in any one of Claims 1-5.   The method according to claim 6, wherein in the polymerization initiating group introduction step, a non-polymerizable functional group is introduced to the substrate surface together with the polymerization initiating group.   The polymerization initiator group and the non-polymerizable functional group are introduced to the substrate surface by immersing the substrate in a solution containing a polymerization initiator and a surface density control agent for the polymerization initiator group. the method of.   The method according to claim 8, wherein the surface density controlling agent of the polymerization initiating group is a functional group that can be immobilized on a substrate and the other end is a non-polymerizable functional group.   The method according to claim 9, wherein the surface density controlling agent of the polymerization initiating group is 2- (4-phenyl) ethylphosphonic acid.

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