JP2003080015A - Recyclable filter material for air filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recyclable filter material for an air filter. SOLUTION: The filter material for an air filter is an easily macerating filter material having organic fibers and minute fibers bonded by an easily macerating binder and is treated with a water repellent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air filter medium which can be recycled as an air filter medium or a papermaking raw material after use.

[0002]

2. Description of the Related Art An air filter is used for cleaning air in ventilation and air conditioning of various facilities. Conventionally, as a filter material used for these air filters, (1) a mixture of chopped strand glass fibers and micro glass fibers is made by a wet papermaking method, and a synthetic resin (acrylic resin emulsion or the like) as a binder, a water repellent (fluorine resin) Glass fiber filter medium (2) which has been added with a system emulsion, etc. and dried (2) Synthetic fiber filter medium which is made into a nonwoven fabric by forming synthetic fibers such as polyester fiber, polypropylene fiber, acrylic fiber by a spunbond method, a melt blow method or the like is mainly used. There is.

In addition to these, in recent years, in many cases, an electretized filter medium has been used in which the synthetic fiber filter medium described in the above (2) is made into an electret, and the dust removal performance is improved by both the action of electrostatic attraction and the filtering action of the nonwoven fabric. Has been done. Although these filter media are discarded after use, there are fewer disposal sites for landfill disposal, and disposal is problematic in view of environmental issues. Although it may be incinerated and disposed of, the used filter medium contains components harmful to the environment, such as heavy metals, and is not a preferable disposal method considering environmental pollution. In recent years, it has been practiced to wash and recycle the air filter as a whole. However, when the air filter is washed and regenerated with a cleaning solution, the regenerated air filter cannot show sufficient performance. Instead, the surfactant contained in the cleaning liquid may remain on the filter, causing a problem.
Although dust collected in the filter is also removed by using ultrasonic waves, the dust is usually removed because the filter medium is assembled into the frame with a complicated shape. Not only was it impossible to apply sufficient ultrasonic energy to the filter medium, but also the dust that had penetrated into the filter medium could not be removed.

[0004]

Therefore, the first aspect of the present invention
The purpose of is to provide a recyclable filter material for an air filter. A second object of the present invention is to provide an air filter medium that can be regenerated as an air filter medium.

[0005]

The above objects of the present invention are as follows: (1) Easy-disintegrating air characterized in that organic fibers and fine fibers are bound with an easily disintegrating water-soluble binder and treated with a water repellent agent. Filter media for filters. (2) Organic fiber has a fiber diameter of 3 to 6 μm and a fiber length of 0.5 to
5.0 mm synthetic fiber and freeness 200-800 mL
(JIS-P8121) is a mixed fiber containing cellulose pulp fibers, the fine fibers are fine fibers having a fiber diameter of 0.1 to 3.0 μm, and the easily disintegrating water-soluble binder is a polyvinyl alcohol-based binder. The filter material for an easily disintegratable air filter according to (1) above. (3) The organic fiber is composed of 80 to 100% synthetic fiber and 20 to 0% of cellulose pulp fiber, and 0.3 to 20 parts of the fine fiber is used for 100 parts of the organic fiber. The filter material for an easily disintegratable air filter according to 1) or (2). (4) Easy disintegration The filter material for an easy disintegration air filter according to any one of (1) to (3) above, wherein powdery or fibrous polyvinyl alcohol is used as the water-soluble binder. (5) Organic fiber is polyester fiber, acrylic fiber,
Synthetic fiber selected from vinylon fiber and bleached softwood kraft pulp (NBKP), bleached hardwood kraft pulp (LB
KP), which is a mixed fiber of cellulose pulp fibers, in which fine fibers are rock wool, alumina fibers, glass fibers, ceramic fibers, whiskers, and a fiber diameter of 3
An aromatic polyamide fiber, a cellulose fiber, an acrylic fiber, a polypropylene fiber, or a polyethylene fiber fibrillated to have a size of not more than μm, which is characterized in that the easy disintegration property according to any one of (1) to (4) above. Filter material for air filters. (6) Easy disintegration The water-soluble binder has a degree of polymerization of 200 to 40.
0, polyvinyl alcohol having vinyl alcohol units and vinyl acetate units having a saponification degree of 30 to 99.9 mol%, carboxyl displacement polyvinyl alcohol,
The silanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, polyvinyl alcohol binder for hydrolyzed paper, the filter material for an easily disintegratable air filter according to any one of (1) to (5) above. Achieved by

The filter material for the easily disintegratable air filter of the present invention will be described in detail below. The organic fiber used in the filter material for the easily disintegratable air filter of the present invention, polyester fiber, acrylic fiber, synthetic fiber such as vinylon fiber,
Cellulose pulp fibers such as softwood (bleached) kraft pulp (NBKP) and hardwood (bleached) kraft pulp (LBKP) and plant fibers such as mercerized fibers thereof are mentioned. Synthetic fibers and cellulose pulp fibers and mercer The mixed fiber with the modified fiber is preferable, and in particular, synthetic fiber selected from polyester fiber, acrylic fiber, vinylon fiber and softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP) and mercerized fiber thereof. Mixed fibers with selected cellulose pulp fibers are preferred. In the mixed fiber of synthetic fiber and cellulose pulp fiber, the synthetic fiber is preferably a synthetic fiber having a fiber diameter of 3 to 6 μm and a fiber length of 0.5 to 5.0 mm, and the cellulose pulp fiber has a freeness of 200 to
800 mL (JIS-P8121), further freeness 4
Preferred is from 00 to 800 mL of cellulose pulp fiber.

In the present invention, the fine fiber is a fiber having a fiber diameter smaller than that of the above-mentioned organic fiber, and the material thereof may be any, and aromatic polyamide (eg, poly-p-phenylene terephthalamide, poly- p-phenylene benzothiazole, poly-p-phenylene benzobisoxazole, polyamide hirarazine, poly-p-phenylene terephthalamide-3,4-diphenyl ether terephthalamide, etc.) pulp-like fiber object, cellulose fiber, acrylic fiber, polypropylene fiber , Synthetic fibers such as polyethylene fibers, rock wool, alumina fibers, glass fibers, ceramic fibers, and whiskers. The fiber diameter of the fine fibers is 0.1 to 3.0 μm
Is preferable, and more preferably 0.3 to
It is in the range of 1.5 μm. Fine fibers of synthetic fibers can be obtained, for example, by fibrillating with a homogenizer so that the fiber diameter is 3 μm or less. The fine fibers thus obtained are preferred for use in the present invention.

In the filter material for easily disintegratable air filter of the present invention, the organic fiber is composed of 80 to 100% of synthetic fiber and 20 to 0% of cellulose pulp fiber, and the fine fiber is 0.3 to 20 per 100 parts of the organic fiber. Part is preferably used. The easily disintegratable water-soluble binder used in the present invention does not disintegrate when the air filter medium of the present invention is wet with water, but is dispersed in water for recycling the easily disintegratable air filter medium of the present invention. Or a bead that allows the fibers to be easily disintegrated when beaten. Examples of these binders include polyvinyl alcohol-based binders, for example, a polymerization degree of 20.
A polyvinyl alcohol having a vinyl alcohol unit and a vinyl acetate unit having a saponification degree of 0 to 400 and a saponification degree of 30 to 99.9 mol%, a carboxyl displacement polyvinyl alcohol, a silanol-modified polyvinyl alcohol, a cation-modified polyvinyl alcohol, or a polyvinyl alcohol binder for hydrolyzing paper is used. Used. The binder may be powdery or fibrous.

The water repellent contained in the filter material for the easily disintegratable air filter of the present invention may be a water repellent used in ordinary air filters, and examples thereof include a fluororesin-based water repellent, a silicone-based water repellent, and a wax. Examples include system emulsions and acrylic resin emulsions. The filter material for an easily disintegratable air filter of the present invention is an organic fiber, a fine fiber and an aqueous slurry prepared by mixing an easily disintegratable water-soluble binder in the form of powder or fibrous material, and the slurry is made into paper using a paper machine. It can be obtained by lightly pressing, applying a water repellent using a size roll or the like, and drying. The filter medium for easily disintegrating air filter of the present invention is used as an air filter, then removed from the frame, dispersed in water by removing accumulated dust, disaggregated by using a disintegrator, and washed away the dust that had bitten into the filter medium, It can be reused as a raw material fiber. Further, the raw material fiber component obtained may be adjusted to produce a filter medium for an air filter.

[0010]

Example 1 Polyester fiber (Tepyrus 0.1d × 3 manufactured by Teijin Ltd.)
mm) 95.0%, conifer bleached kraft pulp (NBK)
P) (Freeness 720 mL) 5.0% mixed fiber 1
For 00 parts, aramid fine fiber (KYC manufactured by Daicel)
An aqueous slurry containing 3.0 parts of -400S) and 4.5 parts of polyvinyl alcohol-based binder fiber (VPB105 manufactured by Kuraray Co., Ltd.) was prepared. This slurry is JIS-P8
209 standard square handmade paper machine, paper weight 54
A sheet of g / m ² was prepared, lightly pressed and dried, and then a water repellent (Asahi Glass Co., Ltd.) was applied using a size press roll.
Manufactured by Balladet PR New) 2% emulsion liquid and dried to obtain a filter medium sheet for a medium performance filter.

With respect to the obtained filter medium sheet, water repellency, tensile strength, collection rate and pressure loss were determined as follows. <Water repellency> JIS-P8137 (Testing method for water repellent degree of paper and board) <Tensile strength> JIS-P8113 (Testing method for tensile strength of paper and board) <Collection rate> JIS-B9927 (Air filter for clean room) Performance test method) Annex 1 (normative) Clean room air filter media performance test method <Pressure loss> Annex 1 (normative) Clean room air filter media performance test method of JIS-B9927 (clean room air filter performance test method) The obtained results are shown in Table 1 together with the material and constitution of the filter medium sheet. As is apparent from Table 1, the obtained filter medium sheet has a performance that is practically no problem as a filter medium for a commonly used air filter for ventilation and air conditioning. Further, the obtained filter medium sheet was examined for disaggregation property and whether it can be re-sheeted as follows. <Disintegration property> The filter medium sheet was disintegrated by a standard disintegrator of JIS-P8209, and the time required for disintegration was determined.

<Re-sheeting> The slurry of the mixed fibers after disaggregation was made into paper using a JIS-P8209 standard square handmade paper machine, a sheet was prepared, lightly pressed and dried, and then repelled using a size press roll. Liquid medication (Asahi Glass Co., Ltd.)
It was observed whether or not the sheet could be re-sheeted by treating it with a 2% emulsion liquid manufactured by Balladet PR New Co., Ltd., drying it and making it into a recycled filter medium sheet. The results obtained are shown in Table 1.

[0013]

[Table 1]

As shown in Table 1, the reclaimed filter medium sheet obtained by re-sheeting showed a practically no problem as a filter medium for a commonly used air filter for ventilation and air conditioning. Further, the slurry of the mixed fibers after disaggregation can also be used as a raw material for recycled paper. Further, the obtained filter medium sheet was subjected to the following atmospheric dust load test and then regenerated to confirm whether the regenerated filter medium sheet could be actually used. The atmospheric dust load test apparatus used for the atmospheric dust load test will be described with reference to FIG. In FIG. 1, 1 is a duct, 2 is a test filter medium holder, 3 is a wire mesh that supports a filter medium sheet, 4 is a differential pressure gauge,
5 is a suction pump, 6 is a flow meter, and 7 is a flow control valve.
By driving the suction pump 5, air is discharged through the duct 1, the suction pump 5, and the flow meter 6. The flow rate of air passing through the duct 1 can be adjusted by opening and closing the flow rate adjusting valve 7. The differential pressure gauge 4 measures the pressure difference between the upstream side and the downstream side of the filter medium sheet set in the test filter medium holder 2. Atmospheric dust load test, filter material sheet φ140m
It was set in a holder of m (effective area 100 cm ² ), and the outside air was continuously ventilated by a suction pump at a wind speed of 5.3 cm / sec, and an atmospheric dust load test was conducted until the ventilation resistance was double the initial value.

After this, the filter medium sheet is stipulated in JIS-P8209.
Was disintegrated with a standard disintegrator of No. 1 to prepare a slurry. The obtained slurry is washed by repeating dehydration and redispersion to remove dust contained therein, and made into a slurry again. The obtained slurry is made into paper using a JIS-P8209 standard square handmade paper machine, and the basis weight is set. Weight 53.0 g / m ²
The sheet is prepared, lightly pressed and dried, then treated with a 2% emulsion liquid of a water repellent (Balajet PR New manufactured by Asahi Glass Co., Ltd.) using a size press roll and dried to obtain a recycled filter medium sheet. It was The pressure loss, the collection rate, and the tensile strength of the obtained recycled filter medium sheet were determined. The obtained results are shown in Table 2 together with the pressure loss, the collection rate and the tensile strength of the new product. As is clear from Table 2, the recycled filter sheet does not show a large decrease in performance, and can be used as an air filter for air cleaning.

[0016]

[Table 2]

Example 2 Acrylic fiber (manufactured by Mitsubishi Rayon Co., Ltd. 0.1 d × 3 m)
m) 95.0%, bleached softwood kraft pulp (NBKP)
(Freeness 720 mL) 5.0% mixed fiber 100
Aramid fine fiber (KY-4 manufactured by Daicel)
An aqueous slurry containing 3.0 parts of 00S) and 4.5 parts of polyvinyl alcohol-based binder fiber (WPB105 manufactured by Kuraray Co., Ltd.) was prepared. This slurry is JIS-P820
9 Standard square handmade paper making machine, basis weight 53g /
After making a sheet of m ² and pressing lightly and drying,
Using a size press roll, treat with a water repellent (Asahi Glass Co., Ltd. Balladet PR New) 2% emulsion liquid,
It dried and the filter medium sheet was obtained.

With respect to the obtained filter medium sheet, water repellency, tensile strength, collection rate and pressure loss were determined in the same manner as in Example 1. The obtained results are shown in Table 1 together with the material and constitution of the filter medium sheet. As is apparent from Table 1, the obtained filter medium sheet has a performance that is practically no problem as a filter medium for a commonly used air filter for ventilation and air conditioning. Also,
With respect to the obtained filter medium sheet, it was observed in the same manner as in Example 1 whether or not it could be disintegrated and re-sheeted. The results obtained are shown in Table 1. The recycled filter media sheet obtained by re-sheeting has shown practically no problem as a filter media for a commonly used air filter for ventilation and air conditioning. Further, the slurry of the mixed fibers after disaggregation can also be used as a raw material for recycled paper.

Example 3 Polyester fiber (Tepyrus 0.1d × 3 manufactured by Teijin Ltd.)
An aqueous slurry containing 14 parts of aramid fine fibers (KY-400S manufactured by Daicel) and 1.0 part of polyvinyl alcohol-based binder fibers (WPB105 manufactured by Kuraray Co., Ltd.) per 100 parts of 100 mm) was prepared. This slurry is JIS
-P8209 Paper was made using a standard square handmade paper machine, a sheet having a basis weight of 55 g / m ² was prepared, lightly pressed and dried, and then a water repellent (a ballast manufactured by Asahi Glass Co., Ltd.) using a size press roll. It was treated with a 2% emulsion liquid and dried to obtain a filter medium sheet for HEPA filter.

With respect to the obtained filter medium sheet, water repellency, tensile strength, collection rate and pressure loss were determined in the same manner as in Example 1. The obtained results are shown in Table 1 together with the material and constitution of the filter medium sheet. As is clear from Table 1, the obtained filter medium sheet has performance that is practically no problem as a filter medium for a HEPA filter used for air cleaning in a clean room or the like. Further, with respect to the obtained filter medium sheet, it was observed in the same manner as in Example 1 whether or not it could be disintegrated and re-sheeted. The results obtained are shown in Table 1. The recycled filter medium sheet obtained by re-sheeting showed a practically no problem as a filter medium for a HEPA filter used for cleaning air in a clean room or the like. Further, the slurry of the mixed fibers after disaggregation can also be used as a raw material for recycled paper.

Further, the obtained filter medium sheet was subjected to an atmospheric dust load test in the same manner as in Example 1 and then regenerated, and it was confirmed whether or not this filter medium sheet could be regenerated after being actually used. Further, the obtained filter medium sheet was subjected to the atmospheric dust load test in the same manner as in Example 1, and then, Example 1
It was regenerated in the same manner as above, and the pressure loss, the collection rate and the tensile strength of the obtained regenerated filter medium sheet were determined. The obtained results are shown in Table 2 together with the pressure loss, the collection rate and the tensile strength of the new product. As is clear from Table 2, the recycled filter sheet does not show a large decrease in performance, and can be used as an air filter for air cleaning.

COMPARATIVE EXAMPLE 1 A commercially available medium-performance air filter medium sheet for ventilation and air conditioning having the material, constitution and performance shown in Table 1 is JIS-
When disaggregated with a standard disintegrator of P8209, a part of the fibers were crushed, and an increase in water resistance of the sheet was observed when the fiber was formed into a sheet with a JIS-P8209 standard square handmade paper machine. In addition, the binder was not dissolved on the surface of the sheet and adhered as a solid fiber mass, and the uniformity of the sheet was not very good. As a result, the tensile strength and the collection rate were remarkably reduced, and the material could not be used as an air filter medium.

Comparative Example 2 A filter material sheet of a commercially available HEPA filter having the materials, constitutions and performances shown in Table 1 was disintegrated by a standard disintegrator of JIS-P8209, and a part of the fibers Was crushed and formed into a sheet by a JIS-P8209 standard square handmade paper machine, the water resistance of the sheet was extremely increased. In addition, the binder was not dissolved on the surface of the sheet and adhered as a solid fiber mass, and the uniformity of the sheet was not very good. As a result, the ventilation resistance was significantly increased, and it did not have the ability to be used as an air filter medium.

Comparative Example 3 A commercially available medium-performance air filter media sheet for ventilation and air conditioning having the materials, constitutions and performances shown in Table 1 was used according to JIS-
Although it was attempted to disintegrate with the standard disintegrator of P8209, it could not be disaggregated.

Comparative Example 4 Medium-performance air filter medium sheet for ventilation and air conditioning [H
-701A manufactured by Hokuetsu Paper Mills Co., Ltd.] was subjected to an atmospheric dust load test in the same manner as in Example 1 and then regenerated in the same manner as in Example 1 to obtain a regenerated filter medium sheet with pressure loss and collection rate. And the tensile strength were determined. The obtained results are shown in Table 2 together with the pressure loss, the collection rate and the tensile strength of the new product. As is clear from Table 2, the recycled filter medium sheet had a remarkably lowered collection rate and tensile strength, and did not have the performance of being usable as an air filter for air cleaning.

COMPARATIVE EXAMPLE 5 A commercially available HEPA air filter medium sheet [O-300
A Hokuetsu Paper Mills Co., Ltd.] was subjected to an atmospheric dust load test in the same manner as in Example 1, and then regenerated in the same manner as in Example 1 to obtain the regenerated filter medium sheet, which had a pressure loss, a collection rate and The tensile strength was determined. The obtained results are shown in Table 2 together with the pressure loss, the collection rate and the tensile strength of the new product. Table 2
As is clear from the above, the recycled filter medium sheet had a significantly increased airflow resistance and did not have the ability to be used as an air filter.

[0027]

EFFECT OF THE INVENTION The filter medium for an air filter of the present invention can be easily disintegrated after use, and the disaggregated fibers can be recycled as a raw material fiber for an air filter filter medium or general recycled paper.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an atmospheric dust load test apparatus.

[Explanation of symbols]

1 duct 2 Test medium holder 3 wire mesh 4 differential pressure gauge 5 suction pump 6 Flow meter 7 Flow control valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhide Murata             1276 Aoyama, Ogawa-cho, Hiki-gun, Saitama Prefecture F-term (reference) 4D019 AA01 BA04 BA05 BA06 BA12                       BA13 BA17 BB05 BC13 BC20                       CB06 DA01 DA03                 4L047 AA04 AA05 AA06 AA07 AA12                       AA13 AA16 AA19 BA09 CC12                       DA00                 4L055 AA02 AA03 AC06 AF04 AF05                       AF16 AF17 AF21 AF27 AF33                       AF35 AG51 AG69 AG86 AH23                       EA05 EA16 EA30 EA32 EA33                       FA30 GA31 GA39

Claims (6)

[Claims] 1. A filter material for an easily disintegrating air filter, wherein organic fibers and fine fibers are bonded with an easily disintegrating water-soluble binder and treated with a water repellent agent. 2. A synthetic fiber having a fiber diameter of 3 to 6 μm and a fiber length of 0.5 to 5.0 mm, and a freeness of 200 to 80.
A mixed fiber containing 0 mL (JIS-P8121) of cellulose pulp fiber, and the fine fiber has a fiber diameter of 0.1 to 3.0 μm.
The easily disintegrating water-soluble binder is a polyvinyl alcohol-based binder, which is a fine fiber of m, and the easily disintegrating air filter medium according to claim 1. 3. The organic fiber is composed of 80 to 100% of synthetic fiber and 20 to 0% of cellulose pulp fiber, and 0.3 to 20 parts of fine fiber is used for 100 parts of organic fiber. The filter material for an easily disintegratable air filter according to claim 1. 4. The easily disintegratable air filter medium according to claim 1, wherein powdery or fibrous polyvinyl alcohol is used as the easily disintegratable water-soluble binder. 5. The organic fiber is a mixed fiber of synthetic fiber selected from polyester fiber, acrylic fiber, vinylon fiber and cellulose pulp fiber selected from softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP). , Fine fiber, rock wool, alumina fiber,
A glass fiber, a ceramic fiber, a whisker, or an aromatic polyamide fiber, a cellulose fiber, an acrylic fiber, a polypropylene fiber, or a polyethylene fiber fibrillated to have a fiber diameter of 3 μm or less. The filter material for an easily disintegratable air filter according to any one of 4 above. 6. The easily disintegratable water-soluble binder has a degree of polymerization of 20.
0 to 400, polyvinyl alcohol having a vinyl alcohol unit and a vinyl acetate unit having a saponification degree of 30 to 99.9 mol%, a carboxyl displacement polyvinyl alcohol, a silanol-modified polyvinyl alcohol, a cation-modified polyvinyl alcohol, and a polyvinyl alcohol binder for hydrolyzing paper. 1 to 5 characterized by
A filter material for an easily disintegratable air filter according to any one of 1.