JP6861200B2 - Resin composition containing volatile organic compound adsorbent and volatile organic compound adsorbent - Google Patents

Description

The present invention relates to a volatile organic compound adsorbent made of MFI-type zeolite.

Zeolite is _{a crystalline aluminosilicate having SiO 2} , Al ₂ O _3, etc. in its skeleton and having regular channels (pores). In particular, MFI-type zeolite is silica-rich and is widely known to contain pores having a 10-membered ring structure (5.1 × 5.5 Å and / or 5.3 × 5.6 Å).

_{It is known that Al 2} O ₃ in the crystal skeleton of zeolite affects the hydrophilicity, and the larger the amount of Al, the higher the hydrophilicity, and the smaller the amount, the lower the hydrophilicity. Silica-rich MFI-type zeolite has low hydrophilicity due to its low Al content, and therefore exhibits high adsorptivity to hydrophobic organic components, and has a pore size close to the size of low-molecular-weight hydrocarbons. Therefore, it has been proposed to use it as an adsorbent for organic compounds (see Patent Documents 1 to 3).

Further, the MFI-type zeolite also has an effect of reducing a peculiar odor (hereinafter referred to as a resin odor) generated due to deterioration of the resin or the like (see Patent Document 4).

By the way, volatile organic compounds such as toluene, xylene, and ethyl acetate (hereinafter, may be abbreviated as VOC) have a large impact on the environment and are known to cause photochemical smog, for example, and air pollution. The concentration of VOCs emitted and scattered from fixed sources such as factories is severely restricted by the Prevention Law. Therefore, there is a demand for an adsorbent for efficiently removing such a volatile organic compound from the exhaust gas.

The above-mentioned MFI-type zeolite is frequently used as a VOC adsorbent because it exhibits high adsorptivity to various organic compounds, but since it has a small adsorption capacity, it is used in a large amount to obtain the desired effect. I needed it. Therefore, it is required to improve the adsorption performance and capacity of MFI-type zeolite with respect to VOC. In particular, there is a demand for an adsorbent capable of exhibiting sufficient adsorptivity even when VOCs such as toluene are present in the atmosphere at a low concentration.

Japanese Unexamined Patent Publication No. H01-171554 Japanese Unexamined Patent Publication No. H09-253483 Japanese Unexamined Patent Publication No. 2003-126689 Japanese Unexamined Patent Publication No. 2002-06915

Therefore, an object of the present invention is to provide a volatile organic compound adsorbent that exhibits excellent adsorptivity even when a volatile organic compound is present at a low concentration. Another object of the present invention is to provide an adsorbent that exhibits excellent adsorptivity particularly for toluene.

Another object of the present invention is to provide a resin composition containing a volatile organic compound adsorbent.

The present inventors have conducted many experiments on the adsorption performance of volatile organic compounds of zeolite. As a result, they have found that the MFI-type zeolite obtained by synthesis at a low temperature exhibits excellent adsorptivity to VOC (toluene) in a low concentration atmosphere, and have completed the present invention.

According to the present invention, in _{a volatile organic compound adsorbent composed of an MFI-type zeolite having SiO 2} / Al ₂ O ₃ (molar ratio) of 50 or more, the zeolite has a (053) plane spacing in the X-ray diffraction spectrum. Volatile (d value) is 2.99 Å or less, and the amount of nitrogen adsorbed at a nitrogen _{partial pressure PN2} (P / P ₀ ^{) 0.005 is 100 (cm 3} / g) or more. Organic compound adsorbents are provided.

The volatile organic compound adsorbent of the present invention is
(1) SiO ₂ / Al ₂ O ₃ (molar ratio) is 90 or more.
(2) The _{amount of toluene adsorbed at the toluene partial pressure P T} (P / P ₀ ) 0.01 is 8.2% by mass or more.
(3) The alkali metal content in terms of oxide is suppressed to 0.1% by mass or less.
Is preferable.

Further, according to the present invention, there is provided a resin composition in which the above-mentioned volatile organic compound adsorbent is blended in a resin.

The resin composition in which the adsorbent of the present invention is blended in the resin is
(1) 0.005 to 100 parts by mass of the adsorbent is blended per 100 parts by mass of the resin.
(2) The resin is a thermoplastic resin.
Is preferable.

As shown in Examples described later, the volatile organic compound adsorbent of the present invention has _{an atmosphere in which the toluene partial pressure P T} (P / P ₀ ) is 0.01, that is, the toluene content is extremely low. The amount of toluene adsorbed in the atmosphere is 8.2% by mass or more, and the highest amount is 9.0% by mass or more. For example, none of the conventionally known MFI-type zeolite-based adsorbents exhibit a toluene adsorptivity of 8.2% by mass or more in such a low toluene concentration atmosphere. Therefore, the volatile organic compound adsorbent of the present invention is preferably supported on an environmental purification facility used in a chemical factory or the like, for example, an exhaust rotor having a honeycomb structure.

An X-ray diffraction image of a volatile organic compound adsorbent made of MFI-type zeolite obtained in Example 2. X-ray diffraction image of the (053) plane of Example 3, Comparative Example 2 and Comparative Example 3. Nitrogen adsorption isotherm measurement results of Example 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3. Toluene adsorption isotherm measurement results of Example 2, Comparative Example 2 and Comparative Example 3. A scanning electron micrograph of a volatile organic compound adsorbent made of MFI-type zeolite obtained in Example 1. A scanning electron micrograph of a volatile organic compound adsorbent made of MFI-type zeolite obtained in Example 6.

The adsorbent made of MFI-type zeolite of the present invention is used for adsorbing and removing volatile organic compounds. The volatile organic compound means an organic compound having a boiling point in the range of 50 to 260 ° C. under atmospheric pressure, and is, for example, toluene, xylene, ethyl acetate, ethanol, benzene, methyl ethyl ketone, dichloroethane, trichloroethane and the like, and is preferable. Is toluene.

<MFI type zeolite>
The MFI-type zeolite used as an adsorbent exhibits an X-ray diffraction peak as shown in FIG. 1 because 10-membered ring-shaped pores peculiar to the zeolite are formed. For example, a sharp diffraction peak of the (011) plane near 2θ = 7.9 °, the (200) plane near 2θ = 8.9 °, and the (051) plane near 2θ = 23.1 ° is shown.
Such zeolites are _{silica-rich with SiO 2} / Al ₂ O ₃ (molar ratio) of 50 or more, preferably 90 or more, more preferably 100 or more, most preferably 5000 or more, and thus have low hydrophilicity and hydrophobicity. It shows excellent adsorptivity for organic compounds with high oxygen content. On the contrary, zeolite having a high aluminum content (the above molar ratio is less than 50) has high hydrophilicity, and excellent adsorptivity to VOC cannot be obtained.

The MFI-type zeolite used in the present invention is produced by a reaction at a low temperature (80 to 130 ° C.), and as a result, the plane spacing (d value) of the (053) plane in the X-ray diffraction spectrum is increased. It is 2.99 Å or less, and the amount of nitrogen adsorbed at a nitrogen _{partial pressure P N2} (P / P ₀ ^{) 0.005 is 100 (cm 3} / g) or more, preferably 103 (cm ³ / g) or more. .. It will be described later that such a d value and the amount of nitrogen adsorbed can be obtained by the reaction at a low temperature.

The above d value represents the distance between specific surfaces of the pores in the zeolite. When the d value is small, the zeolite has no strain, the pores are uniformly distributed, and the pore volume is also large.
That is, this MFI-type zeolite has micro-sized pores of the above-mentioned size densely and uniformly distributed in relation to having a small d value as described above, and as a result, as a result, As described above, the nitrogen partial pressure P _N2 (P / P ₀ ) shows a large amount of nitrogen adsorption even in a low atmosphere of 0.005. In other words, showing the amount of nitrogen adsorbed as described above means that micro-sized pores are densely distributed, and as a result, it is extremely excellent for volatile organic compounds, especially toluene. It can exhibit adsorptivity.

Further, in the above-mentioned MFI type zeolite, the amount of alkali metal (hereinafter referred to as alkali) in terms of oxide is suppressed to 1.70% by mass or less, preferably 1.25% by mass or less, particularly 0.1% by mass or less. It is desirable to be there. That is, such an alkali content (for example, Na or K) is mixed in the zeolite as an unavoidable impure component in the production method, but if this amount is large, the hydrophilicity of the zeolite increases and it is organic. Although the adsorptivity to the components is greatly reduced, in the present invention, since such an alkali amount is suppressed to a small amount, the decrease in the adsorptivity to the organic compound due to the alkali is effectively avoided, and as a result, the adsorbability to the organic compound is effectively avoided. , High adsorptivity to VOC can be ensured. For example, as shown in the examples below, MFI-type zeolite used in the present invention, toluene adsorption amount in an atmosphere toluene partial pressure P _{T (P} / P ₀₎ is 0.01 8. When the amount of alkali in terms of oxide is suppressed to 0.1% by mass or less, which is 2% by mass or more, it is 9% by mass or more, and particularly shows an adsorption amount of toluene close to 10% by mass.

<Manufacturing of MFI type zeolite>
The above-mentioned MFI-type zeolite is heated in a mixed gel containing a silica source and an alumina source in the presence of a template and seed crystals, preferably in the presence of an alkali metal hydroxide for the preparation of a raw material described later. It is produced by reacting a silica source and an alumina source (crystallization).

The silica source is _{preferably one having a high SiO 2 purity from which impurities such as Na 2} O and Al ₂ O ₃ have been removed to some extent. For example, tetraethyl orthosilicate, colloidal silica, silica gel dry powder, silica hydrogel and the like are used. .. These silica sources are once dissolved in an aqueous solution during the reaction and reconstructed into MFI-type zeolite. However, if there are few impurities or non-reactive components unnecessary for the reaction, the type of silica source is MFI-type zeolite. Does not significantly affect crystallization.
However, from the viewpoint of cost, silica gel dry powder or silica hydrogel, which can be produced by a relatively simple method, is preferable, and silica hydrogel is particularly desirable. In the silica hydrogel, for example, an alkali silicate such as sodium silicate is gradually added dropwise to a mineral acid such as sulfuric acid under stirring to bring the final pH to about 3.0 to 9.0, and after filtration, the silica hydrogel is discharged after washing with water. It can be easily obtained by washing until the pH of the liquid reaches about 5.0 to 7.0. The silica hydrogel may be produced by heating while mixing the raw materials or before and after washing with water, or at room temperature.
Further, as the alumina source, for example, aluminum sulfate, basic aluminum sulfate, sodium aluminate and the like can be used, but sodium aluminate is particularly preferable.
The mixing gel, like a MFI-type zeolite of _SiO 2 / _Al 2 _{O 3} higher than the molar ratio _SiO 2 / _Al 2 _{O 3} as a target (molar ratio), for example, MFI-type molar ratio 112 When zeolite is obtained, it contains a Si component and an Al component, such as setting the molar ratio of the mixed gel to 120. Generally, a silica source and an alumina source are mixed in an aqueous medium at room temperature. Obtained by doing.

The silica source and the alumina source are _{mixed so that SiO 2} / Al ₂ O ₃ (molar ratio) has a predetermined amount ratio, but an MFI-type zeolite containing a particularly large amount of Si component (for example, a molar ratio of 1000). In the case of producing the above), the use of an alumina source can be omitted. That is, the raw material used for industrial use may contain a small amount of Al component as an unavoidable impurity.

The mixed gel containing the silica source and the alumina source is further mixed with the template and the seed crystal, preferably further the alkali metal hydroxide, and as a mixed gel containing the seed crystal, the temperature is low in the presence of the template and the seed crystal. MFI-type zeolite can be obtained by reacting with and crystallizing.
The method of adding the template, the seed crystal, and the alkali metal hydroxide is not particularly limited, and a part or all of the mixed gel and / or a part or all of the raw material of the mixed gel can be added in advance prior to crystallization. Can be mixed and used.

The template is a structure-determining agent for forming 10-membered ring-shaped pores peculiar to MFI-type zeolite, and is an amine compound containing an n-alkyl group having 2 to 4 carbon atoms and a nitrogen cation in the molecule, for example. , tetraalkyl (ethyl, n- propyl or n- butyl) ammonium cation and an anion (e.g., Br ^-) hydroxides such salts and the ammonium and are used.

That is, during the reaction of the silica-alumina hydrosol (SiO chain by condensation), an intermediate containing an electric charge is generated and a Si—O—Si chain is formed as shown in the following schematic formula.
^{OH-Si-O - + SiOH} → [OH-Si-O ... SiOH] -
→ OH-Si-O-Si ^- OH
→ OH-Si-O-Si (-OH) -O - + H 2 O
Upon chaining Si-O-Si as described above, the cations of the template above protect the intermediate, and at the same time, a chain of Si-O-Si is formed so as to surround the cations of such a template, resulting in the result. As a result, a 10-membered ring structure peculiar to MFI-type zeolite can be formed.

For example, in the case of tetrapropylammonium bromide (TPA-Br), such a template is _{used in an amount of TPA / SiO 2} = 0.03 to 0.20 (molar ratio) with respect to the Si component of the mixed gel. However, this amount varies greatly depending on the type of template, especially the carbon number of the alkyl group.
It is not necessary when the above quaternary ammonium hydroxide is used as a template, but when a salt of quaternary ammonium and an anion such as Br or Cl is used as a template, the silica source is dissolved. _{Therefore, an alkali metal hydroxide (for example, caustic soda) of A 2} O / SiO ₂ = 0.01 to 0.20 (molar ratio, A is an alkali metal element) is added to the Si component of the mixed gel. .. In this case, the larger the amount of alkali metal hydroxide added, the shorter the time required for crystallization can be obtained. However, when A ₂ O / SiO ₂ exceeds 0.20, the obtained MFI-type zeolite contains the effect. A large amount of alkali metal that acts hydrophilicly may remain, and the adsorptivity of the present invention may not be sufficiently exhibited. Therefore, it is preferable that A ₂ O / SiO ₂ is 0.15 or less, and particularly preferably 0.10 or less.

Further, in order to produce the above-mentioned MFI-type zeolite, it is necessary to carry out the above reaction at a low temperature, specifically, 80 to 130 ° C., preferably 95 to 120 ° C., particularly preferably 95 to 98 ° C. .. Therefore, the above reaction must be carried out in the presence of seed crystals. As a result, crystallization is promoted, and crystallization can be completed in a short time, for example, 48 hours or less, particularly 20 hours or less, while carrying out the reaction at a low temperature.
As such a seed crystal, it is necessary to use the MFI-type zeolite prepared in advance, but among the production methods described later, the MFI-type zeolite containing a template may be used, for example, firing or the like. The MFI type zeolite from which the template has been removed may be used. This seed crystal is appropriately pulverized and then used in an amount of 0.02 to 20 parts by mass, preferably 0.05 to 5.0 parts by mass per 100 parts by mass of _{SiO 2 with} respect to the Si component of the mixed gel. To.
When the amount of the seed crystal added is 0.05 parts by mass or less, the effect of shortening the time required for crystallization is weak. When the amount added is excessive, the composition of the seed crystal affects the composition of the obtained MFI-type zeolite, and an unnecessary interface is formed by, for example, core-shelling. It is not desirable because it inhibits the formation of distributed pores. In particular, when the amount is 5.0 parts by mass or more, there is no significant change in the time required for crystallization, which increases the amount of seed crystals used and leads to cost increase, which is not desirable.

Further, as described above, the reaction of the mixed gel (mixed gel containing seed crystals) in the presence of the template and the seed crystal is carried out at 80 to 130 ° C., whereby the d value and the amount of nitrogen adsorbed described above are carried out. It is possible to obtain a silica-rich MFI-type zeolite showing the above.
For example, when MFI-type zeolite is produced by a conventionally known method, the reaction temperature is set to a high temperature of about 180 ° C., or at least about 150 ° C., whereby crystallization can be completed in a short time. According to the research by others, when the reaction is carried out at a temperature higher than 130 ° C., the d value (plane spacing of the (053) plane) of the obtained MFI-type zeolite exceeds 2.99 Å, and the nitrogen content When the pressure _PN2 (P / P ₀ ) is 0.005, the amount of nitrogen adsorbed is ^{lower than 100 (cm 3} / g). The reason for this has not been clarified exactly, but if the reaction is carried out at a high temperature, the template will thermally decompose during the crystallization of the MFI-type zeolite, or even if the template does not thermally decompose, the thermal energy of the template will cause it. It is not because the vibration is promoted, and as a result, the effect of the template that protects the intermediate is weakened, the crystal structure of the obtained MFI-type zeolite is distorted, or the pores formed are distorted. The present inventors presume that.
That is, in the present invention, since the reaction is carried out at a low temperature as described above, decomposition and vibration of the template due to thermal energy are avoided, and as a result, strain of the obtained zeolite and distortion of pores are prevented, and the size is uniform. The pores can be densely distributed, and therefore, it is considered that the obtained MFI-type zeolite has a small surface spacing d value of a specific surface ((053) surface) and exhibits a large amount of nitrogen adsorption. Is. In particular, the fact that the d value of the (053) plane is as small as 2.99 Å or less as in the present invention indicates that the MFI-type zeolite has an extremely dense crystal structure, that is, micro-sized pores are formed. It can be said that it is an MFI-type zeolite that is densely and uniformly distributed. Usually, in the analysis of the d value of zeolite, it is difficult to be confused with other peaks in the XRD measurement range, and it is preferable to use a peak on a relatively high angle side (for example, around 30 °). In the case of the MFI-type zeolite, the (053) plane meets this condition, and it is analyzed that the volatile organic compound adsorbent made of the MFI-type zeolite of the present invention has a dense crystal structure.
Although it is possible to crystallize the MFI-type zeolite even when the reaction temperature is 80 ° C. or lower, the progress of the reaction becomes extremely slow, which makes it impractical.

In the present invention, the strain of the zeolite obtained as described above and the distortion of the pores are prevented, and the pores having a uniform size can be densely distributed. As a result, a high BET ratio is obtained as in the examples described later. It has a surface area. That is, the volatile organic compound adsorbent of the present invention has a BET specific surface area of ^{430 m 2} / g or more, preferably 440 m ² / g or more, and particularly preferably 450 m ^{2 / g or more.}

Further, as long as the reaction temperature is in the above low temperature region, this reaction may be carried out under atmospheric pressure or under pressure using an autoclave or the like, but there is not much merit even if it is carried out under pressure. However, since crystallization is sufficiently promoted even when the seed crystals are used under atmospheric pressure, it is preferable to carry out the reaction under atmospheric pressure from the viewpoint of cost and the like.

After the above reaction, after washing with filtered water and drying according to a conventional method, firing is carried out at a temperature of about 500 to 800 ° C. for about 0.5 to 10 hours, whereby the template in zeolite is removed. It is possible to obtain an MFI-type zeolite in which pores suitable for adsorption of a target VOC, particularly toluene, are densely distributed.

If a large amount of alkali such as Na or K is used in the synthesis of the above-mentioned zeolite, the alkali content becomes large and these alkalis act hydrophilicly, so that the obtained MFI-type zeolite is organic. The adsorptivity to the compound is greatly impaired. In this case, the MFI type zeolite that has undergone the firing step is dispersed again in the aqueous solution, and the dealkali method using an acid such as hydrochloric acid or sulfuric acid, or the ion exchange between alkali and ammonium using various ammonium salts, and the subsequent firing for removing ammonium. It is desirable to remove the alkali content by a series of dealkalising methods.
In particular, a series of dealkalising methods using various ammonium salts is preferable. In this case, for example, it is preferable to use about 10 to 200 parts by mass of ammonium chloride with respect to the calcined MFI-type zeolite, and the subsequent removal of ammonium is performed. The firing for this purpose is preferably carried out at 300 to 600 ° C. for about 0.5 to 10 hours.

The MFI-type zeolite thus obtained usually has a medium diameter of 0.1 to 20 μm, preferably 0.5 to 10 μm, but is preferably pulverized into a powder as appropriate and used for handling. In consideration of the ease of use, the particle size is adjusted to a size of 1.0 to 4.0 μm before use. However, for example, when it is kneaded into a resin composition or mixed with a liquid containing a hydrophobic solvent such as a paint or a coating agent, it is submicron order (medium) in order to improve dispersibility and increase the specific surface area. It can also be used after being further finely pulverized to a surface area of 0.1 to 1.0 μm). Further, when filling equipment such as an adsorption column or an adsorption tower, for example, after appropriately mixing with a commonly used binder, it can be molded and used as a granular material.

The volatile organic compound adsorbent of the present invention composed of the above-mentioned silica-rich MFI-type zeolite exhibits high adsorptivity to volatile organic compounds typified by toluene, xylene, and ethyl acetate, and these compounds have a low concentration. These compounds can be effectively adsorbed and removed even in the atmosphere existing in. Therefore, such an adsorbent is preferably supported on an environmental purification facility used in a chemical plant or the like that discharges a gas containing a volatile organic compound, for example, an exhaust rotor having a honeycomb structure.

Further, the volatile organic compound adsorbent of the present invention having such characteristics is blended with a resin and used for preparation of a resin composition, and preferably a masterbatch is prepared from the obtained resin composition to form a film or various kinds. Various articles such as members are molded. At this time, the volatile organic compound adsorbent of the present invention can be added to the resin alone or in combination with other adsorbents and additives. The blending amount of the volatile organic compound adsorbent of the present invention is not limited, but for example, the adsorbent is in the range of 0.001 to 1000 parts by mass, preferably 0.005 to 100 parts by mass per 100 parts by mass of the resin. Can be blended. In particular, when the adsorbent of the present invention is applied to a resin for the purpose of reducing unreacted monomers during resin processing and the peculiar resin odor generated due to deterioration, the adsorbent is 0.005 to 100 parts by mass of the resin. It is preferably 10 parts by mass.
In addition, by adding the volatile organic compound adsorbent of the present invention to the resin used for automobile parts and housing materials, the odor peculiar to new cars and new buildings, especially substances that cause sick house syndrome (toluene and aldehydes). It can be expected to have the effect of improving the living environment, such as adsorbing (kind), and can be made into a highly functional fiber having a deodorizing function by containing it in the fiber in the fiber processing process. In such a case, the amount of the adsorbent is preferably 1 to 100 parts by mass per 100 parts by mass of the resin.

As the base resin, either a thermoplastic resin or a thermosetting resin can be used, but from the viewpoint of moldability, the thermoplastic resin is preferable. Examples of such a thermoplastic resin include the following.
Random or block copolymers of α-olefins such as low density polyethylene, high density polyethylene, polypropylene, poly1-butene, poly4-methyl-1-pentene or ethylene, propylene, 1-butene, 4-methyl-1-pentene Olefin-based resins such as polymers and cyclic olefin copolymers;
Ethylene-vinyl acetate copolymers such as ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, and ethylene-vinyl chloride copolymers;
Styrene-based resins such as polystyrene, acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer;
Vinyl-based resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, methyl polyacrylate, and polymethyl methacrylate;
Polyamide resins such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12;
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, and copolymerized polyesters thereof;
Polycarbonate resin;
Polyphenylene oxide resin;
Biodegradable resins such as polylactic acid;
The thermoplastic resins exemplified above can be used individually, but can also be used as a blend of two or more kinds.
In the present invention, an olefin resin and a polyester resin are particularly preferable, and an olefin resin is the most suitable as a base resin.

Further, since the volatile organic compound adsorbent of the present invention has micro-sized pores densely and uniformly distributed, the active sites (for example, solid acid points) of the MFI-type zeolite are also densely and uniformly distributed. It is expected that there will be. That is, the volatile organic compound adsorbent of the present invention is used for catalysts to which MFI-type zeolite is generally applied, such as acid catalysts, disproportionation catalysts, isomerization catalysts, hydrocarbon synthesis catalysts, FCC catalysts, and olefin polymerization catalysts. It does not limit its use as a catalyst, a denitration catalyst, etc., or as a catalyst carrier.

The present invention will be described with reference to the following experimental examples.
Various measurements in the experiment were carried out by the following methods.

(1) X-ray diffraction (measurement and analysis conditions for surface spacing d-value analysis)
A dry sample was placed in a desiccator whose relative humidity was adjusted to 75%, and allowed to stand at room temperature for 48 hours or more to adsorb a saturated amount of water. X-ray diffraction measurement was performed on the sample taken out over 2Θ = 29.6 to 30.2 °. The X-ray diffraction measurement was performed with Cu-Kα using Ultima4 manufactured by Rigaku Co., Ltd. under the following conditions.
Target: Cu
Filter: Curved Crystal Graphite Monochromator Detector: SC
Voltage: 40kV
Current: 50mA
Step size: 0.005 °
Counting time: 10sec / step
Slit: DS2 / 3 ° RS0.3mm SS2 / 3 °
The d value (Å) was calculated based on the following formula for the angle having the maximum peak in the X-ray diffraction in the target range.
(Bragg's condition)
d = nλ / 2sinΘ
d: Interplane spacing n: Integer λ: Wavelength sin Θ: Angle formed by crystal plane and X-ray (confirmation of crystal type)
The crystal was confirmed by changing the following conditions among the conditions used for measuring the d value.
Measuring range: 3-40 °
Current: 40mA
Step size: 0.02 °
Counting time: 0.6sec / step

(2) the measurement of the measurement the nitrogen adsorption of the nitrogen adsorption isotherm, using the Tristar made of micromeritics Co., nitrogen partial pressure _P N2 _(P / _{P 0)} is an adsorption isotherm in the range from 0.005 to 0.95 I asked. The pretreatment was carried out under vacuum conditions at 200 ° C. for 2 hours. For each adsorbent described later, the _{measured value at a nitrogen partial pressure P N2} (P / P ₀ ) of 0.005 was defined as the nitrogen adsorption amount (cm ³ / g).

(3) Measurement of toluene adsorption isotherm For the measurement of toluene adsorption, Belsolp manufactured by Nippon Bell Co., Ltd.
Using Max, _{the adsorption isotherm in the range of toluene partial pressure PT} (P / P ₀ ) of 0.0001 to 0.10 was determined. The pretreatment was carried out under vacuum conditions at 150 ° C. for 2 hours. The equilibrium determination time was set to 300 seconds. For toluene, a chromatographic grade manufactured by Wako Pure Chemical Industries, Ltd. was used. For each adsorbent described later, the _{measured value at a toluene partial pressure PT} (P / P ₀ ) of 0.01 was converted into the adsorbed amount per adsorbent unit mass and used as the toluene adsorbed amount (mass%).

(4) Composition analysis For elemental analysis necessary for calculating the alkali metal content and SiO ₂ / Al ₂ O ₃ (molar ratio) in terms of oxide, Rigaku ZSX primus II manufactured by Rigaku Co., Ltd. was used as the target. Rh, the analysis line was Kα, and the others were measured under the following conditions.
The sample was dried at 110 ° C. for 2 hours as a reference.

(5) Measurement of medium diameter (D50%) The medium diameter (μm) on a volume basis was measured using a laser diffraction type particle size distribution measuring device Mastersizer 3000 manufactured by Malvern Co., Ltd. and water as a solvent. ..

(6) BET specific surface area The specific surface area by the BET method was calculated from the adsorption isotherm obtained in (2).

(Comparative Example 1)
_{Silton MT-100 (SiO 2} / Al ₂ O ₃ = 105), which is an MFI type zeolite manufactured by Mizusawa Industrial Chemicals Co., Ltd., was used. Shilton is a registered trademark of Mizusawa Industrial Chemicals Co., Ltd.

(Comparative Example 2)
HSZ890HOA, an MFI type zeolite manufactured by Tosoh Corporation, was used.

(Comparative Example 3)
ABSCENTS-3000, an MFI-type zeolite manufactured by Union Showa Co., Ltd., was used.

(Comparative Example 4)
(Preparation of silica hydrogel)
Silica hydrogel using 40% by mass sulfuric acid and No. 3 sodium silicate (SiO ₂ = 22.8% by mass, Na ₂ O = 7.6% by mass, H ₂ O = 69.6% by mass) by a conventionally known method. Was prepared. When the composition was analyzed, SiO ₂ = 38.5% by mass, Na ₂ O = 0.02% by mass, and H ₂ O = 61.4% by mass.
(Synthesis of MFI type zeolite)
In a 2 L stainless steel jug, silica hydrogel, TPA-Br, 49% by mass NaOH and water are added in a molar ratio of SiO ₂ : Na ₂ O: TPA-Br: H ₂ O = _{with a SiO 2 mass of 200 g.} Mixing was performed at room temperature and stirring so as to be 1: 0.025: 0.045: 16, and a mixed gel was prepared.
Next, the mixed gel was transferred to a 1.5 L autoclave with a built-in stirring blade, and the temperature was raised to 170 ° C. in 2.5 hours under stirring conditions, and after the temperature rise, a crystallization reaction was carried out for 12 hours while maintaining 170 ° C. It was. After completion of the reaction, the liquid was filtered, and subsequently washed with water having a volume three times that of the mixed gel to obtain an MFI-type zeolite containing a template. The median diameter of the MFI-type zeolite after washing with filtered water was 10.0 μm.
After drying in a constant temperature drying shelf at 110 ° C. for 10 hours, the template was removed under the condition of holding at 600 ° C. for 2 hours using a muffle furnace to obtain an MFI-type zeolite containing no template.
(Crushing MFI type zeolite)
The MFI type zeolite was pulverized using a swivel jet mill. The median diameter of the powder after pulverization was 7.7 μm.

(Example 1)
Comparison except that the composition of each component was changed to SiO ₂ : Na ₂ O: TPA-Br: H ₂ O = 1: 0.03: 0.05: 16 in terms of molar ratio, with the mass of SiO _{2 being 200 g.} A mixed gel was prepared in the same manner as in Example 4, and finally 1.0% by mass of seed crystals (MFI-type zeolite having a medium diameter of 7.7 μm obtained in Comparative Example 4) were added to _{SiO 2 and further added.} Stirring was performed for 5 minutes to prepare a mixed gel containing seed crystals.
Next, under stirring conditions, the mixed gel containing seed crystals was heated to 95 ° C. in 1 hour in a temperature-controllable warm water layer, and a crystallization reaction was carried out for 20 hours while maintaining 95 ° C. After completion of the reaction, the reaction solution was filtered and subsequently washed with water having a volume three times that of the mixed gel to obtain an MFI-type zeolite containing a template. The median diameter of the MFI-type zeolite after washing with filtered water was 1.0 μm.
After drying in a constant temperature drying shelf at 110 ° C. for 10 hours, the template was removed under the condition of holding at 600 ° C. for 2 hours using a muffle furnace to obtain an MFI-type zeolite containing no template.
Then, the MFI-type zeolite was pulverized using a swivel jet mill in the same manner as in Comparative Example 4 to obtain a volatile organic compound adsorbent composed of the MFI-type zeolite. The median diameter was 1.0 μm.

(Example 2)
To 10 g of the volatile organic compound adsorbent made of MFI-type zeolite of Example 1, 90 g of water was added and redispersed by stirring, and then 10 g of ammonium chloride was added and exchange treatment was carried out for 3 hours. After washing with filtered water, the obtained ammonium-MFI type zeolite is dried in a constant temperature drying shelf at 110 ° C. for 10 hours, and then ammonium is removed using a muffle furnace under the condition of holding at 500 ° C. for 3 hours to dealkalinate. -MFI type zeolite was obtained. This zeolite was pulverized again using a swirling jet mill to obtain a volatile organic compound adsorbent made of MFI-type zeolite. The median diameter was 1.0 μm.

(Example 3)
A volatile organic compound adsorbent made of MFI-type zeolite was obtained by the same operation as in Example 1 except that the reaction vessel was a 1.5 L autoclave with a built-in stirrer, the reaction temperature was 105 ° C., and the reaction time was 16 hours. It was. The median diameter was 2.0 μm.

(Example 4)
The composition of the mixed gel was set to SiO ₂ : Na ₂ O: TPA-Br: H ₂ O = 1: 0.025: 0.045: 16 in terms of molar ratio, and the reaction vessel was a 1.5 L autoclave with a built-in stirrer for reaction. A volatile organic compound adsorbent made of MFI-type zeolite was obtained by the same operation as in Example 1 except that the temperature was 110 ° C. and the reaction time was 18 hours. The median diameter was 4.0 μm.

(Example 5)
_{A mixed gel using sodium aluminate (Al 2} O ₃ = 23.0% by mass, Na ₂ O = 19.2% by mass, H ₂ O = 57.8% by mass) in addition to the raw materials shown in Example 1. At room temperature and under stirring so that the composition of is SiO ₂ : Al ₂ O ₃ : Na ₂ O: TPA-Br: H ₂ O = 1: 0.008: 0.05: 0.04: 16 in terms of molar ratio. The mixture was mixed, and finally 1.0% by mass of seed crystals (MFI-type zeolite having a medium diameter of 7.7 μm obtained in Comparative Example 4) was added to _{SiO 2 to prepare a mixed gel containing seed crystals.} Then, a volatile organic compound adsorbent made of MFI-type zeolite was obtained by the same operation as in Example 1 except that the reaction vessel was a 1.5 L autoclave with a built-in stirrer and the reaction temperature was 120 ° C. The median diameter was 1.8 μm.

(Example 6)
The _{mass of SiO 2} was 380 g, the MFI-type zeolite having a medium diameter of 1.0 μm obtained in Example 1 was used as a seed crystal, the amount of the seed crystal added was 3.0% by mass, and the composition of each component was in molar ratio. A mixed gel containing seed crystals is mixed under stirring conditions so that _{SiO 2} : Na ₂ O: TPA-Br: H _{2 O = 1: 0.03: 0.045: 20.} Was prepared. Subsequent operations were the same as in Example 1 to obtain a volatile organic compound adsorbent made of MFI-type zeolite. The median diameter was 0.7 μm.

(Example 7)
Using the same raw materials as in Example 5, the _{mass of SiO 2} was 240 g, the MFI-type zeolite having a medium diameter of 0.7 μm obtained in Example 6 was used as a seed crystal, and the amount of the seed crystal added was 2.0% by mass. , So that the composition of each component is SiO ₂ : Al ₂ O ₃ : Na ₂ O: TPA-Br: H ₂ O = 1: 0.0077: 0.12: 0.04: 20.3 in terms of molar ratio. The raw materials including the seed crystals were mixed under stirring conditions to prepare a mixed gel containing the seed crystals. Then, a volatile organic compound adsorbent made of MFI-type zeolite was obtained by the same operation as in Example 1 except that the crystallization reaction was set to 48 hours. The median diameter was 0.5 μm.

Tables 2 and 3 show the test results of the physical characteristics, nitrogen adsorption amount, and toluene adsorption amount of the MFI-type zeolites of Comparative Examples 1 to 4 and the volatile organic compound adsorbents prepared in Examples 1 to 7.

Application example: Preparation of a resin composition containing an adsorbent The adsorbent of Example 6 was mixed with polyethylene pellets (product name LF440B) manufactured by Japan Polypropylene Corporation, and 170 using a lab plast mill manufactured by Toyo Seiki Seisakusho. By melt-kneading at ° C. and cutting into chips, a resin composition having an adsorbent compounding amount of 0.5 part per 100 parts by mass of the resin was obtained. No components other than the adsorbent were added.

Evaluation of resin odor adsorption capacity;
The resin odor reduction performance was evaluated using the resin composition containing the adsorbent and the polyethylene pellets containing no adsorbent obtained in the preparation of the above resin composition.
Weigh 5 g each of the resin composition containing the adsorbent or the polyethylene pellet containing no adsorbent in a 500 mL screw mouth storage bottle, wrap the screw part of the bottle with Teflon tape in triplicate, and close the lid. And sealed. This was prepared for each subject (for 5 people). A storage bottle containing polyethylene pellets was placed in a constant temperature shelf dryer preheated at 50 ° C., and left as it was at 50 ° C. for 90 hours. Two types of storage bottles were taken out from the constant temperature shelf dryer, and immediately after opening, the odor was smelled, and the degree of odor (0: no odor, 1: faint odor, 2: odor) was evaluated by each subject. The test was conducted without knowing which pellet was contained in the subject. The test results are shown in Table 4.

Claims (6)

In a volatile organic compound adsorbent composed of MFI-type zeolite having _{SiO 2} / Al ₂ O _{3 (molar ratio) of 50 or more,}
The zeolite has a plane spacing (d value) of the (053) plane in the X-ray diffraction spectrum.
99 Å or less
It has a BET specific surface area of 430 m ² / g or more, and has a BET specific surface area of 430 m 2 / g or more.
Moreover, the amount of nitrogen adsorbed at a nitrogen partial pressure of _PN2 (P / P ₀ ^{) of 0.005 is 100 (cm 3} / g) or more.
A volatile organic compound adsorbent having a toluene adsorption amount of 8.2% by mass or more at a toluene partial pressure P _T (P / P _{0) 0.01.} The adsorbent according to claim 1, wherein SiO ₂ / Al ₂ O ₃ (molar ratio) is 90 or more. The adsorbent according to claim 1 or 2, wherein the alkali metal content in terms of oxide is suppressed to 0.1% by mass or less. A resin composition in which the adsorbent according to any one of claims 1 to 3 is blended in a resin. The resin composition according to claim 4, wherein the adsorbent is blended in an amount of 0.005 to 100 parts by mass per 100 parts by mass of the resin. The resin composition according to claim 4, wherein the resin is a thermoplastic resin.

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