JPS61271031A - Adsorptive foam plastics - Google Patents

Abstract

PURPOSE:To give strong and rapid adsorbability by burying one part of a very slender carbon fiber into the plastic material surrouding continuous foams and by exposing the rest of the activated carbon fiber in said foams. CONSTITUTION:An infinite number of continuous foams 2 communicating each other are partitioned by a hardened foam urethane membraneous substance 1 and an infinite number of very slender activated carbon fibers 3 (about 7-15mu in diameter, about 0.3-2.5mm in length) are protruded and exosed in these foams 2. One part of the length is kept by the urethane membranenous substance whose thickness is 1/several-1/10mm or less and said substance does not fall of easily. The micropores of the fiber surface are not colsed or disturbed by other substances, so the part protruded into the foams 2 of the activated carbon fiber 3 are directly contacted with the gas or liquid flowing in the continuous foams 2, thus offensive smelling ingredients in the gas or harmful ingredients can be adsorbed and removed rapidly and strongly.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is a foamed plastic that is foamed by mixing fine length activated carbon fibers and has bad odor adsorption properties, in particular, the fiber surface of the activated carbon fibers is foamed as much as possible. This invention relates to foamed plastics that have been exposed to air, water, and other fluids to have the ability to strongly and rapidly adsorb malodorous substances.

[Conventional technology and its problems]

In foamed plastics having open cells, such as foamed polyurethane, the cells are continuous from one surface to the ground like a three-dimensional network, allowing air and other fluids to flow therethrough. Therefore, this type of foamed plastic can be used as an air filter material for the purpose of removing fine dust from the air. However, since the size of bubbles is much larger from a molecular level, they do not have the ability to capture molecules of malodorous substances and do not have adsorption performance.

Foaming for the purpose of imparting bad odor adsorption ability, j? Attempts to mix powdered or granular activated carbon into IJ urethane have been made because if it is a fine powder, most of the activated carbon will be buried in the polyurethane, and there will be no opportunity for it to come in contact with the air flowing through the open cells. They have not been successful because they are ineffective, and large particle sizes do not have sufficient mechanical retention due to the polyurethane material and easily fall off, making them unsustainable for long-term use.

On the other hand, activated carbon fibers, i.e., organic materials such as phenolic fibers or cellulose rayon fibers, are used as a starting material and carbonized at about 600 to 800°C in an inert atmosphere, and then heated to 60°C in the presence of water vapor or CO2.
Carbon fibers, which have been activated at temperatures of about 0 to 1000° C. to develop numerous micropores on their surfaces, have attracted much attention in recent years because of their strong and rapid adsorption ability. The micropores of activated carbon fibers are developed directly on the fiber surface, and these play a major role in adsorbing malodorous and harmful substances. Conventional granular activated carbon also has micropores, but in the case of granular activated carbon, the micropores that participate in adsorption are formed deep inside the relatively large openings, rather than the micropores opening directly on the surface. Therefore, the adsorption effect is indirect and takes time. On the other hand, activated carbon fibers have micropores directly formed on the fiber surface without passing through large openings, so the adsorption rate and desorption rate are extremely rapid, and the adsorption effect is also strong.

However, activated carbon fibers, which have excellent adsorption and desorption ability, cannot maintain a certain shape by themselves, so there are problems with ease of handling, and until now they have not been fully utilized as adsorbents or filtration materials. I can't say that it is. -For example, an attempt was made to make an air filter by making activated carbon fibers into paper, but the micropores on the surface of the activated carbon fibers made into paper were blocked.
In addition to not being able to demonstrate its full potential, paper as a substrate lacks mechanical strength and easily crumbles, and it also has the limitation that it cannot be used as a filter material for water or other liquids.

[Purpose of the invention]

Therefore, the present invention provides a filter material that is sufficiently strong and can be used repeatedly, which can be used for both gas and liquid phases by combining activated carbon fiber, which has excellent adsorption and desorption ability, with foamed plastic without reducing its ability. Or it is intended to be made into an adsorbent.

Specifically, an object of the present invention is to provide an adsorbent foamed plastic that has strong and rapid adsorption ability by mixing activated carbon fibers cut into fine lengths into plastic and foaming the plastic.

[Summary of the invention]

The adsorptive foamed plastic of the present invention has open cells,
The plastic material that forms (or surrounds) these bubbles retains a portion of the length of the fine long activated carbon fibers, while the rest of the length of the activated carbon fibers is exposed within the bubbles. Therefore, as many micropores as possible on the fiber surface can come into direct contact with the fluid passing through the bubbles.

In the present invention, the fine long activated carbon fiber is obtained by cutting a continuous long filament into fine lengths of about 0.3 to 2.5 m, and if this is a foamed plastic raw material, such as polyurethane foam, it is mixed with a polyol. Then,
When this mixture is mixed with a diisocyanate and foamed, a foamed polyurethane containing activated carbon fiber is obtained in which part of the polyurethane is retained as polyurethane and the rest is exposed in the cells, as described in - above. The activated carbon fibers exposed or protruding within the cells do not block the micropores on their surface, so they come into direct contact with air, water, or other fluids flowing through the open cells, and quickly and powerfully remove fine particles of malodorous substances. Adsorb. If the foamed plastic is thermosetting,
Since the plastic material has sufficient strength, it can even be used to adsorb odor components in hot water.

[Embodiments of the invention]

First, the microscopic structure of the adsorptive foamed plastic of the present invention will be explained with reference to the drawings. The figure is a partial sectional view showing an adsorbent foamed urethane as a preferred embodiment of the present invention, enlarged several hundred times.

This foamed polyurethane is a soft, highly foamed material, and has countless open cells 2 that are separated by a urethane film 1 formed by foaming and hardening, but are in communication with each other. The long fine activated carbon fibers 3 protrude or are exposed. Each activated carbon fiber 3 has a portion of its length held by the urethane film 1, and does not fall off easily.

The portion of the activated carbon fiber 3 that protrudes into the cell 2 comes into direct contact with the gas or liquid flowing within the open cell 2 because the micropores on the fiber surface are not blocked or obstructed by any other substance as described above. The odor components or harmful components therein can be quickly and strongly adsorbed and removed.

If you closely observe the activated carbon fiber 3, if it is relatively long, for example about 2.0 mm long, the activated carbon fiber 3 will be 31 mm long in the figure.
As shown, it extends across several bubbles 2, and is buried and held in the urethane film 1 in the middle or at the ends. The urethane film has a thickness on the order of 1/10 or less, and although it does not completely bury the carbon fiber over its entire length, it does not bury the carbon fiber over a certain length. Keep it buried.

When the activated carbon fiber 3 is relatively short, for example, about 0.3 m long or less as shown at 32, it is generally held by pricking one end into the urethane film 1, and the remaining part is effectively filled with air bubbles. It stands out within 2.

Activated carbon fibers, which can be mixed into polyurethane to effectively enable its foaming, actually have a length of about 0.3 Wrm to about 2
．． It was recognized that it existed up to about 5 Yamicho. 0.
3 If the material is shorter than the container, for example, if it is pulverized to 0.2 ra or less, the proportion of the material buried in the urethane material after foaming will increase, reducing the amount of micropores that participate in adsorption. It has been found that carbon fibers longer than about 2.5 mm, for example 3 mm or more, are less likely to be retained by the urethane film and tend to reduce the mechanical strength of the urethane film itself. The diameter of the activated carbon fibers was about 7 to 15 microns (μ), and good results were obtained with any thickness within this range.

The example illustrated and explained above is a case of flexible highly foamed polyurethane, but as long as the fine long activated carbon fibers are expanded in open cells so that part of their length is exposed, other foamed plastics, such as continuous The adsorptive foamed plastic of the present invention can also be obtained by using foamed vinyl chloride, foamed polyethylene, foamed polypropylene, foamed rubber, etc. having air bubbles.

Next, a specific example of a method for producing adsorbent foamed polyurethane, which is a preferred example of the adsorptive foamed plastic of the present invention, will be described.

Example 1 A filament of activated carbon fiber manufactured by Courtaulds, UK (some of which has the trade name As, diameter of about 8 μm) is pulverized to a length of about 1.2 corals and used. Polyol, diisocyanate, which is the main raw material of flexible polyurethane foam, and the above-mentioned pulverized fiber are mixed in a ratio of 100:3.
Use at a volume ratio of 5:20. The polyol and pulverized fibers were placed in a foaming mold, stirred thoroughly at room temperature, diisocyanate was added, and the mixture was further stirred to foam.

The foamed molded product was pale black to dark gray, and numerous activated carbon fibers were observed protruding from the open cells. Almost no fibers were completely trapped and buried in the urethane film.

Example 2 The same procedure as Example 1 was repeated except that the volume ratio of polyol, diincyanate, and crushed activated carbon fiber was 100:35:25. The color of the foamed molded product was almost the same as Example 1, and the inside of the cells was The protrusion status of the activated carbon fibers was also almost the same.

Example 3 The same procedure as in Example 1 was carried out, except that the volume ratio of 4-liol, diisocyanate, and crushed activated carbon fiber was 100:35:15.

The color of the foamed molded product was slightly paler than that of Example 1, and it was not observed that the protrusion of activated carbon fibers into the cells was significantly reduced.

Adsorption Test To examine the adsorption performance of the activated carbon fiber-containing foamed plastic of the present invention, the following samples were prepared.

Sample ■... 6 pieces of foamed polyurethane produced according to Example 1
After leaving it at room temperature for a day, I cut it into 3 5.02 square pieces.

Sample ■... 3 pieces of foamed polyurethane produced according to Example 1
After boiling in hot water for 0 minutes, heat to 100℃ in an electric constant temperature dryer.
After drying for 3 hours, the pieces were left to cool at room temperature and cut into 5 square pieces.

Sample ■...3 sets of commercially available granular activated carbon 5.02 each.

Take 400 cc of water from tap water at a room temperature of 20°C and a water temperature of 10°C into 4 beakers, and add 0-T residual chlorine measurement solution to each beaker. Add 3 drops (approximately 0.IP) of gin and stir well. The water in each beaker is colored the same color due to the chlorine content. One beaker is used for comparison, and the above samples (1), (2), and (2) are immersed one by one in the other three beakers, and the time until the water coloring completely disappears is measured with the naked eye. The following table shows the results of repeating the test three times using three samples of each sample.

Sample times Color disappearance time I 1 2 minutes 2 2 minutes 3 1 minute II 1 3 minutes 2 3 minutes 3 2 minutes m 1 5 minutes 92
5 minutes 9 3 5 minutes The color became paler than that of the comparison beaker after 5 minutes, but it did not disappear completely after that.

In the above tests, Samples I and ■ are activated carbon fibers dispersed in foamed polyurethane, whereas Sample ■ is granular activated carbon itself without any other medium or substrate, so it is possible to use a single weight of only the active ingredient. It can be seen that activated carbon fibers, which have a much smaller amount in comparison, adsorbed chlorine more quickly and strongly than granular activated carbon. It is thought that the reason why the adsorption rate of sample (1) is slower than that of sample I is probably because the boiling treatment caused the activated carbon fibers in a free state to fall off, despite the intended activation effect.

Similar tests were carried out on the foams prepared in Examples 2 and 3, 4 +
7 urethane, but it was not recognized that the adsorption rate was faster than in Example 1 with the one in which the ratio of activated carbon fiber was increased (Example 2);
), the adsorption time was slightly longer, but the coloring completely disappeared.

The adsorbent foamed plastic of the present invention can be effectively used as an adsorbent/filtration material for a gas phase, for example, in an air filter, in addition to the above-described adsorbent or filtration material for a liquid phase. Preferably, the activated carbon fiber-containing foamed polyurethane (especially highly foamed polyurethane) of the present invention eliminates bad odors in the air, such as bad odors emitted from garbage and rotten food, cigarette odors, and sweat and grime odors trapped indoors. It can be strongly removed. −
As an example, the adsorbent foam polyurethane of the present invention (with a thickness of about 6
When the air conditioner was installed at the indoor air intake port of a room air conditioner, the above-mentioned foul odor that was expected to fill the room disappeared in less than 30 minutes. A similar effect can also be achieved when installed over the inlet of a car air conditioner.

In particular, it was able to powerfully remove tobacco odors that tend to linger or stick inside the vehicle interior, keeping the interior clean. moreover,
The adsorbent foam of the present invention, i?, is applied to the circulating air suction side of the fan installed in the refrigerator. When +7 urethane was applied,
Internal components unique to refrigerators have been effectively and powerfully removed.

When the adsorbent foam plastic of the present invention is used as such an air filter, the adsorption capacity will decrease after a long period of time. By injecting and passing hot steam, the activated carbon fibers can be easily detached and used repeatedly.

〔Effect of the invention〕

According to the present invention, activated carbon fiber, which has not been fully utilized in spite of its excellent ability, can be widely utilized as a convenient and useful adsorbent or filter material. The activated carbon fiber-containing foamed plastic of the present invention has faster and stronger adsorption ability than conventional powdered or granular activated carbon, and can be used repeatedly over a long period of time. It can be used as a filter material. This low price is achieved by using expensive activated carbon fibers in the minimum amount necessary for the adsorption effect, and by using foamed plastic as the medium or support material to maintain the product shape, and the foamed plastic is made of activated carbon fibers. This is also due to the synergistic bond between activated carbon fiber and foamed plastic, which has open microcells that are suitable for maximizing the adsorption capacity of activated carbon fibers.

[Brief explanation of the drawing]

The figure is a partial sectional view microscopically enlarging a cross section of a preferred embodiment of the adsorptive foam plastic according to the present invention. 1...Plastic material (urethane film material) 2...Open cell 3...Fine long activated carbon fiber

Claims (1)

[Claims] 1. A part of activated carbon fibers having a fine length is embedded in the plastic material surrounding the cells of a foamed plastic having open cells, and the remaining activated carbon fibers are exposed within the cells. Adsorbent foam plastic characterized by: 2. The activated carbon fiber has a diameter of about 7 to 15 μm and a length of about 0.3 μm.
2.5 mm, and the plastic material has a wall thickness of a fraction of 1 mm to 1/10 or less of 1 mm. 3. The adsorptive foamed plastic according to claim 2, wherein the activated carbon fibers having a length of about 0.3 mm have one end buried in the plastic material and the other end protruding into the cells. 4. The activated carbon fiber having a length of about 1.5 mm has a certain part of its length embedded in the plastic material, and the remaining part of its length is exposed over several bubbles. Adsorbent foamed plastic according to item 2. 5. The adsorbent foamed plastic according to claim 1, wherein the foamed plastic is foamed polyurethane. 6. The polyurethane foam is suitable for air circulation;
6. The adsorbent foamed plastic according to claim 5, wherein the activated carbon fiber is suitable for adsorbing malodorous substances in the air. 7. The adsorptive foamed plastic according to claim 5, wherein the foamed polyurethane is suitable for circulating water, and the activated carbon fiber is suitable for adsorbing odor substances dissolved in water.