JPH035204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a filter that collects mutagens floating in the air.

(Prior art and its problems) In recent years, environmental health and public health problems, such as noise, soot, exhaust gas, and tobacco smoke, have been brought into focus, and the public has become nervous about the pollution problems caused by these.

In particular, many reports have been published regarding tobacco smoke, some of which have been recognized as containing carcinogenic substances, and are attracting attention. Recently, non-smoking vehicles and special spaces such as non-smoking seats have been added. It has been announced that such carcinogens are even present in the smoke from grilling meat and fish.

Such carcinogens have been found to exist among substances that exhibit mutagenic properties. Mutagenicity is a property that changes genetic properties, and generally speaking, if a substance is found to be mutagenic by the Ames test using Salmonella, there is a high probability of 80% or more that the substance is carcinogenic. It is being For example, 3,4 benzpyrene, dimethylnitrosamine, and tryptophan pyrene (tryptophan) contained in tobacco smoke.
1 and TripP-2) are mutagenic substances, and dimethylnitrosamine in particular is recognized to be strongly carcinogenic. Such substances harmful to the human body are contained in large amounts in sidestream smoke when tobacco is left uninhaled, rather than in mainstream smoke (smoke that is inhaled).

In any case, there is no doubt that there are large amounts of substances harmful to the human body floating in the air, and it is also true that they are particularly present in large quantities in areas where there are many cigarette smokers.

In this contemporary background, removing such harmful substances from the air in living spaces is an important environmental measure, and it is predicted that improvements in this direction will be increasingly demanded in the future.

(Objective of the Invention) The present invention provides a technology for collecting mutagens present in the air as one of such environmental improvement measures.

The present invention is based on the discovery that mutagenic substances can be selectively collected when a filter is constructed of crosslinked strongly acidic cation exchange fibers having sulfonic acid groups.

(Structure of the Invention) The present invention is characterized by having a filter made of crosslinked strongly acidic cation exchange fibers having sulfonic acid groups containing 1 to 60% by weight of water as a constituent component, and having a structure that satisfies the following formula. A filter for collecting mutagens in the air.

0.0017W≦H≦0.030W [However, W: The basis weight of the filter (g/m ² ), H: The thickness of the filter (mm). ] (Description of structure) The crosslinked strongly acidic cation exchange fiber having a sulfonic acid group in the present invention refers to a crosslinked strongly acidic cation exchange fiber having a sulfonic acid group, which is formed by crosslinking to an ion exchange polymer such as polystyrene, polyvinyl alcohol, polyamide, polyphenol, or polyethylene.
and refers to fibers into which sulfonic acid groups have been introduced.

Among the above ion exchange polymers, poly(monovinyl aromatic compounds), particularly polystyrene polymers, are preferred because of their excellent chemical stability. Specific examples include polymers made of polystyrene, α-methylstyrene, vinyltoluene, vinylxylene, chloromethylstyrene, and the like. Such polymers need to be crosslinked when introducing sulfonic acid groups. For example, by heat treatment in the coexistence of poraformaldehyde and sulfuric acid, an insolubilized crosslinked polymer having sulfonic acid groups can be obtained.

The amount of sulfonic acid groups introduced into the polymer is at least 0.1 meq/g based on the dry weight of the polymer,
Preferably 0.5meq/g or more, more preferably
It is in the range of 1.0 to 10meq/g. The amount of such exchanged groups can be controlled by processing conditions, introduction process, etc. Furthermore, among the crosslinked strongly acidic cation exchange fibers having sulfonic acid groups thus obtained, fibers made of an ion exchange polymer and a reinforcing polymer are preferably used, with the ion exchange polymer being the main component of the sheath component and the reinforcing polymer being the core component. Ion-exchange fibers based on multifilamentary mixed and composite fibers are preferred because they have sufficient operational mechanical strength and shape retention.

The crosslinked strongly acidic cation exchange fibers constituting the filter of the present invention chemically adsorb mutagenic substances, and therefore it is important that they contain 1 to 60% by weight of water.

The crosslinked strongly acidic cation exchange fiber becomes capable of chemically adsorbing mutagens in the air only when the exchange group is dissociated and activated in the presence of moisture. Therefore, a high moisture content is preferable, but if it exceeds 60% by weight, ventilation resistance increases and is not practical, while if it is less than 1% by weight, mutagenic substances cannot be chemically adsorbed, resulting in extremely poor collection performance. decreases to For this reason, it is more preferable to add 5 to 30% by weight of water. This moisture content is determined by the following formula.

Moisture content (%) = [(wet fiber weight - dry fiber weight) / wet fiber weight] x 100 Such cross-linked strongly acidic cation exchange fibers having sulfonic acid groups chemically adsorb mutagens floating in the air. The amount of adsorption is larger than that of weakly acidic ion exchange fibers having carboxylic acid groups. The amount of adsorption varies depending on the frequency of contact with the fibers, and it is preferable that a large amount of the fibers exist in the filter, and at least
It is 30% by weight, more preferably 50% by weight or more.

As a fiber component constituting the filter of the present invention, in addition to the cation exchange fibers, nonionic ordinary fibers may be contained as reinforcing materials or physical adsorption materials. The nonionic ordinary fibers include natural fibers or recycled fibers such as cotton, rayon, pulp, linen, and wool, synthetic and semi-synthetic fibers such as acetate, polyester, polyamide, and polyolefin, and inorganic fibers such as glass. and activated carbon fiber.

The filter of the present invention is characterized in that it has excellent adsorption capacity and adsorption life for mutagens and is highly durable, and has extremely high efficacy especially when used for a long period of time. Such performance is greatly influenced by the amount of cation exchange groups contained within the filter and the structure of the filter.

The filter of the present invention is required to continuously perform its function for a long period of at least one month, preferably six months or more.

To achieve such requirements, the amount of cation exchange groups in the filter should be on average at least
1.0meq/g, preferably 1.5meq/g or more, especially
2.0meq/g or more is preferable.

Furthermore, the filter of the present invention must have a filter structure that satisfies the following formula.

That is, 0.0017W≦H≦0.030W, preferably 0.002W≦H≦0.01W, particularly preferably,
0.003W≦H≦0.006W [However, W: The basis weight of the filter (g/m ² ), H: The thickness of the filter (mm). ] A filter structure that satisfies the following relationship is selected in order to exhibit a synergistic effect with the above amount of cation exchange groups. That is, even if the amount of cation exchange groups is satisfied, if the above-mentioned filter structure is not present, the number of times of contact with the mutagen is insufficient, which is not preferable because the substance leaks or pressure loss increases.

Among such filters, filters having a W (fabric weight) of at least 50 g/m ² , preferably 100 g/m ² or more are particularly suitable for collecting mutagens. If the basis weight is too small, the leakage of the substance will increase, which is not preferable.

The filter of the present invention that satisfies the above amount of cation exchange groups and filter structure has excellent mutagen collection efficiency, has no trouble due to pressure loss, can withstand long-term practical use, and can extremely effectively remove mutagens. Demonstrates the ability to collect.

A filter that satisfies these conditions may be composed only of the crosslinked strongly acidic cation exchange fibers, but may also be composed of a mixture of other fibers. Filters can be made of paper, non-woven fabric, woven or knitted fabric, or a mixture of these.
It may be in any form. Among these forms, filters that combine a filter layer made of nonionic ordinary fibers and a filter layer made of crosslinked strongly acidic cation exchange fibers share the functions, that is, the nonionic fiber filter layer performs physical adsorption. A filter having a structure in which components are removed as much as possible and mutagens are adsorbed by a crosslinked strongly acidic cation exchange fiber filter layer is preferable from the viewpoint of collection efficiency and durability.

(Effects of the Invention) The filter of the present invention is characterized by highly efficient collection of mutagenic substances floating in the air and by its extremely long lifespan. The present invention can be used, for example, in cooking areas, smoking living spaces, vehicle spaces such as inside cars, ships, and airplanes, company spaces such as conference rooms and offices, coffee shops, movie theaters, entertainment halls, and lobbies of hotels and station buildings. It is extremely effectively applied to spaces where people gather, such as homes and hospitals, especially spaces where vulnerable people such as children and the sick coexist.

The present invention will be explained below by giving examples.

Example 1 Polystyrene (manufactured by Asahi Dow Co., Ltd.: Styron #683)
46 parts of polypropylene (manufactured by Mitsui Toatsu Chemical Co., Ltd.: Noblen JH-G) as a sea component, and 50 parts of polypropylene (same as above) as an island component at a spinning temperature of 270°C for sea-island composite fibers. Melt-spun with a spinneret (16 islands) at a yarn speed of 800 m/
An oil agent was applied while winding at min. obtained
350d, 42fil. multifilament fiber length 1.0mm
It was cut into

To 1 g of cutlet fiber obtained, add 22.5 ml of concentrated sulfuric acid and 30 mg of paraformaldehyde,
After reacting at 80° C. for 4 hours, the obtained fibers were washed with distilled water and air-dried.

The exchange capacity of the obtained fiber is 3.0meq/g-Na
It was a crosslinked strongly acidic cation exchange fiber having H-type sulfonic acid groups.

A portion of this fiber was further mixed with 400 ml of water per 1.0 g (dry weight equivalent) of the ion exchange fiber using a mixer (mixer VA-835 manufactured by Hitachi, Ltd.).
was added and mixed for 3 minutes. The fibers obtained were fibrillated.

Disperse this fiber in water and make it with a basis weight of 150.
A paper was made using a polypropylene nonwoven fabric of g/m ² as a filter cloth. The obtained sheet-like material was dried in a hot air dryer at 60° C. to obtain a filter having a fabric weight of 300 m ² /g and a thickness of 1.5 mm, containing polypropylene fiber as a reinforcing component.

Add moisture to this filter to reach a moisture content of 15
A wet filter was obtained which was % by weight. This filter had a two-layer structure in which the front surface had a layer in which a large amount of cross-linked strongly acidic cation exchange fibers were distributed, and the back surface was a polypropylene fiber nonwoven fabric.

Using this filter, a tobacco sidestream smoke test was conducted using the following method.

Test conditions (1) Cigarette brand: Mild Seven (2) Burning speed: 15 min/1 cigarette (3) Linear ventilation speed: 6 cm/sec (4) Ambient temperature: 20°C (5) Cross-linked strongly acidic cation exchange fiber in filter Amount: 2g (absolutely dry weight) The test was conducted by burning 10 cigarettes and sucking up the sidestream smoke while adjusting it with an aspirator and passing it through a bullet barrel. The filter was placed in the cylinder, weighing 2 g (absolutely dry weight) of crosslinked strongly acidic cation exchange fibers, and the mutagen was adsorbed.

As Comparative Example 1, the same test was conducted using 2 g of commercially available felt activated carbon fiber.

As a result, the filter of the present invention adsorbed 225 mg, whereas the filter of Comparative Example 1 adsorbed only 150 mg. Regarding the evaluation of mutagen trapping performance, we performed the Ames test and found that
As shown in Fig. 2 and Fig. 2, there was a marked difference between the two. That is, FIG. 1 shows the test results with the TA98 strain, and FIG. 2 shows the test results with the TA100 strain. As is clear from the figure, the filter of the present invention was shown to be extremely effective against both reading frame shifting mutagens (Figure 1a) and base conversion mutagens (Figure 2c). On the other hand, Comparative Example 1 showed extremely low results in both cases (FIG. 1b, FIG. 2d).

Comparative Example 2 The cation exchange fibers used in Example 1 (before the mixer treatment) were mixed with the same amount of a web made of polypropylene fibers with a length of 50 mm to make a felt-like filter (basis weight 300 g/ ^m2 ,
11mm thick). The obtained filter was weighed so that the cation exchange fiber contained 2 g (absolutely dry weight), and a smoke test was conducted in the same manner as in Example 1. The amount of smoke adsorption was extremely small at 103 mg, and the mutagen trapping performance evaluation showed that the trapping performance was comparable to that of the felt-like activated carbon fiber of Comparative Example 1, which was worse than that of the present invention.

Comparative Example 3 1.5 parts of acrylic acid, 4.5 parts of methacrylic acid, 0.1 part of ammonium persulfate, and 0.4 parts of a commercially available reducing agent (trade name "Super Light C") were placed in a reaction tank containing nylon staple (diameter: 25 μm) tow. and 93.5 parts of water at a bath ratio of 1:10, reacted at 80°C for 60 minutes, and washed with water.
A cation exchange fiber having a carboxylic acid group was obtained by adding sodium carbonate and carrying out a substitution reaction at 60°C for 30 minutes, followed by washing with water (exchange capacity:
4.5meq/g, water content 1.5).

After activating the above-mentioned cation exchange fiber having a carboxylic acid group with an acid, it was washed with water and dried. then 50
It was cut into mm pieces to make felt using a known method (fabric weight: 300 g/m ² , thickness: 3 mm). After weighing 2 g of the obtained felt and adding water to make the moisture content 15% by weight, a smoke test was conducted in the same manner as in Example 1. The amount of smoke adsorption was as small as 120 mg, and in the evaluation of the mutagen trapping performance, it was slightly better than Comparative Example 1 and worse than that of the present invention. This is because the reactivity of cation exchange fibers having weakly acidic groups such as carboxylic acid is lower than that of the present invention.

Comparative Example 4 Crushed sulfonated carbon with a particle size of 0.5 to 5 mm (manufactured by Hokutan Kagaku Kogyo Co., Ltd., sulfonic acid group content 1.3 meq/g, weak acid group content 2.5 meq/g) was passed through a 16-mesh sieve,
The passed sulfonated carbon was evenly sprinkled on a polypropylene nonwoven fabric with a basis weight of 75 g/ ^m2 (150 g/ ^m2 ).
g amount), then polypropylene nonwoven fabric (basis weight 75 g/
m ² ) and sandwiched in a sandwich pattern to create a three-layered filter. The obtained filter was weighed to contain 2 g of sulfonated carbon, and a smoke test was conducted in the same manner as in Example 1. The amount of smoke adsorption was 82 mg.
In the mutagen collection performance evaluation, the collection performance was comparable to that of Comparative Example 1, which was worse than that of the present invention.

Sulfonated carbon contains weakly acidic groups with low reactivity, has a small capacity for sulfonic acid groups, and is granular and therefore has a small surface area, which is thought to result in poor collection performance. Furthermore, since sulfonated carbon is granular, it is difficult to give it a shape, and it takes time to produce a uniform sheet.

[Measurement of adsorbed substances] 50 ml of ethyl alcohol and 10 ml of 30% ammonia water
The filter that had been tested was immersed in the mixed solution, and the filter was shaken for 2 hours and filtered. The filtrate was evaporated to dryness and the weight of the dried product was measured.

The amount of adsorbed material was evaluated by the total amount of the filtrates obtained from the two treatments described above that were collected and evaporated to dryness.

[Measurement of mutagenic substances]: Ames test The above adsorbed substances were dissolved in 10 ml of dimethyl sulfoxide, and compared with Salmonella typhimurim TA98 strain.
For TA100 strain, each by PCB induction
Evaluation was performed using S9mix and preincubation methods.

[Brief explanation of the drawing]

Figure 1 shows the generation of mutant bacteria with respect to the amount of sample added per plate when using the TA98 strain.
This is a graph showing an increase in the number of His ⁺ reversion mutations, and FIG. 2 is a graph when the TA100 strain is used. In the figure, a, c: data of the filter of the present invention, b, d: data of the activated carbon fiber filter.

Claims (1)

[Scope of Claims] 1. A filter consisting of a crosslinked strongly acidic cation exchange fiber having sulfonic acid groups containing 1 to 60% by weight of water, and having a structure satisfying the following formula: A filter for capturing mutagens in the air. 0.0017W≦H≦0.030W [However, W: The basis weight of the filter (g/m ² ), H: The thickness of the filter (mm). ]