JPS6220847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an adsorbent/desorbent that maintains excellent adsorption/desorption ability over a long period of time.

As an adsorbent and desorber, so-called granulated coal has good air permeability, but its adsorption and desorption rate is poor and its shape is unstable.
On the other hand, powdered activated carbon has a good adsorption/desorption rate, but lacks air permeability and also has poor morphological stability.

Conventionally, a method of fixing powdered activated carbon to a porous substrate using an adhesive solution or emulsion is known, but relatively low molecular weight adhesives and impurities invade the pores of activated carbon (even in emulsion type). This has the disadvantage that activated carbon particles with small particle diameters and particles (intrusion) reduce the adsorption capacity inherent to activated carbon, and that an adhesive film is formed on the surface of activated carbon particles, reducing the adsorption capacity.

As a result of intensive research in order to obtain an adsorbent/desorber with good adsorption/desorption rate and air permeability, the present invention has discovered an effective method for fixing powdered charcoal with good adsorption/desorption rate to a porous substrate, and the manufacturing method of the present invention has been developed. reached. That is, in the present invention, a porous base material mainly composed of polyurethane resin is impregnated in advance with a treatment liquid containing a hot-melt resin, and after drying, activated carbon particles and hot melt adhesive powder are applied to the treatment agent. The method is characterized in that the porous base material is penetrated into the interior of the porous base material, and then heated to a temperature higher than the bonding temperature of the hot-melt adhesive and the hot-melt adhesive.

According to the present invention, the surface pores of the activated carbon particles are not blocked, the excellent adsorption and desorption properties inherent to activated carbon are maintained, and the activated carbon particles have good air permeability with little decrease in air permeability. It has the characteristics that it can be easily and sufficiently fixed and maintains excellent adsorption and desorption ability for a long period of time.

The porous base material used in the present invention means a three-dimensional porous structure, and includes, for example, nonwoven fabrics made of long fibers and/or short fibers, woven and knitted fabrics, bulky paper, synthetic paper, synthetic resin foams, and the like. Among them, synthetic resin foams and their composite base materials can have high porosity, and if the cell membrane is removed, air permeability increases significantly and pressure loss is reduced. It is a particularly preferred material because it is possible to

In the present invention, the heat-melting resin applied to the porous base material in advance is higher than that of the porous base material used.
Usual thermoplastic resins having a low melting point of 20°C or higher are mentioned, and specific examples include polyethylene, polyvinyl acetate, various acrylic ester polymers, methacrylic ester polymers, polyesters, polyamides, polyurethanes, etc. Examples include copolymers and/or mixtures. In some cases, nitrogen-containing cationic resins are preferred. In addition, the resin is applied to the substrate in the form of an emulsion or dispersion of these resins, or an organic solvent solution. During processing, pigments, dyes, flame retardants, and
Plasticizers, fragrances, antioxidants, light stabilizers, bactericides, etc. can also be added. In addition, foaming agents may be added to the processing solution to prevent the resin from sticking to the pores of the porous substrate in the form of a film, alcohol may be added to reduce the viscosity of the processing solution, and the temperature of the processing solution may be increased. It is preferable to do so. The method of applying the treatment liquid is not particularly limited, but it is usually preferable to apply the treatment liquid to the inside with two dips and two nips using the pad method. After treatment, it is then dried at a temperature of 80~80℃.
About 120°C is preferable. If the temperature is too high, the resin may migrate to the surface of the base material. In order to prevent migration, migration inhibitors are added to the processing solution, and crosslinking components are introduced to the extent that the resin does not lose its thermoplasticity.
Also effective are methods such as heating with microwaves for drying, and applying vacuum or pressurized gas before or during drying. When using a resin, especially in an emulsion system, after drying it is heated to a temperature higher than the melting temperature of the resin.
It is preferable to form a film on the substrate.

The amount of resin applied depends on the base material, but is usually 3 to 50%.
% by weight, preferably 5 to 20% by weight,
Preferably it is 5 to 20% by weight.

The porous substrate coated with the hot melt resin is then dried and then typically coated with a mixture of activated carbon particles and hot melt adhesive powder. As activated carbon,
The material used is one obtained by carbonizing and activating wood, coconut shells, animal bones, coal, etc., and then crushing and pulverizing the material. The activity greatly depends on the pores of the particles, but in the present invention, the pore radius is 5 Å or more, 1000 Å or more.
Å or less is preferable. If it is less than 5 Å, it is difficult for the substance to be adsorbed to enter, and if it exceeds 1000 Å, the specific surface area decreases, resulting in a decrease in adsorption performance. Furthermore, if the particle size of the activated carbon is too large, the adsorption performance tends to decrease, so it usually needs to be smaller than 30 mesh, and preferably smaller than 40 mesh.

Hot-melt adhesive powder used in combination with activated carbon particles includes polyethylene, ethylene α
Commonly used materials such as olefin copolymers, ethylene/vinyl acetate copolymers or partially saponified products thereof, polyamides, polyesters, etc. may be used, and although the particle size is not particularly limited, those having a particle size of 60 μm or less are preferable. Also, good results are often obtained when foaming agents, fillers, etc. are incorporated into the adhesive. Further, the blending ratio of the powder to the activated carbon is preferably 5 to 30% by weight based on the total amount of both. If the amount is less than this, the fixing effect will be poor, and if it is more than this, there will be a problem of large pressure loss. The method of applying the mixture is as follows:
Usually, it is preferable to spread the mixture on the above resin-treated porous substrate while applying vibrations to the substrate, or to spread the mixture and then apply vibrations to make it penetrate into the inside. In some cases, the adsorptivity can be accelerated by charging the base material. Optionally, the activated carbon and hot melt adhesive may be mixed on the substrate. In some cases, activated carbon particles and hot melt adhesive powder may be dispersed and applied in water, a water/organic solvent mixture, a water/inorganic salt mixture, a nonsolvent for hot melt adhesive, or the like. Although the amount of activated carbon particles to be applied varies depending on the application, it is usually about 10 to 300% by weight based on the product. After applying the mixture, the hot-melt resin and the hot-melt adhesive are fused or fixed by heat treatment to obtain an adsorption-desorption body.

The thus obtained adsorbent/desorbent exhibits excellent effects when used in air purification, air conditioning filters, ozone filters, organic gas filters, gasoline adsorption/desorption, inorganic gas filters, deodorizing filters, and the like.

The present invention will be explained below with reference to Examples.

In addition, parts and percentages in the examples are based on weight unless otherwise specified.

Example 1 Polyurethane foam (thickness 10 mm) with 13 standard cells/25 mm was mixed with 20 parts of ethylene/vinyl acetate copolymer aqueous emulsion (Tocryl GM-118 Teikoku Kagaku Sangyo Co., Ltd.) and silicone softener (Noran Silicone Softner Dainippon). Ink Company) 2 and water 78
Padding with processing liquid (squeezing rate 100%)
After drying (80°C), heat treatment was performed at 150°C for 2 minutes.

On the other hand, activated carbon powder (pore radius 15~30Å, 250~
2 parts of hot melt type adhesive powder (200 to 300 mesh) of ethylene/vinyl acetate copolymer were added to 10 parts (300 mesh) and thoroughly mixed.

The mixture was sprinkled onto one side of the foam treated with the resin, applied to the inside of the foam while being vibrated, and then heat-treated in an open oven at 160° C. for 3 minutes. Next, the other side of the foam was subjected to the same treatment, and the excess activated carbon was removed while vigorously vibrating at room temperature.

The amount of activated carbon deposited on the urethane foam thus obtained was 56.6%. The obtained adsorbent/desorbent is 20
The ozone decomposition rate was 92% when air containing 1 ppm of ozone at ℃ was passed through at a wind speed of 0.5 m/sec.

Meanwhile, 20 parts of Tocryl GM-118, 20 parts of activated carbon powder
A comparative adsorption/desorption body with activated carbon adhesion of 190% was obtained by padding and drying with a treatment solution consisting of 60 parts and 60 parts of water. The ozone decomposition rate of the obtained adsorbent/desorbent was 13%.

Further, in the case of the present invention, there was almost no decrease in air permeability, whereas the comparative example showed a decrease of about 30%.

Claims (1)

[Claims] 1. A porous base material mainly composed of polyurethane resin is impregnated with a treatment liquid containing a heat-melting resin,
After drying, activated carbon particles and hot melt adhesive powder are applied, the treatment agent is allowed to penetrate into the porous substrate, and then heated to a temperature higher than the bonding temperature of the hot melt resin and hot melt adhesive. A method for manufacturing an adsorbent/desorbent.