JPH0620491B2 - Filter material for air filter and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is a laminated paper comprising an ultrafine glass fiber layer and a compounding fiber layer made of polyvinyl alcohol fiber, which is strong and has excellent collection efficiency. The present invention also relates to an air filter material having high productivity.

<Prior Art> The recent industrial development has been remarkable, and technological innovations such as precision industry, electronic industry, pharmaceutical industry, and food industry have been made rapidly. It is in the clean room that makes this possible. Materials for air filters generally used in clean rooms (hereinafter referred to as materials)
In most cases, the ultrafine glass fibers are used alone, or the wet process is performed by fixing the acrylic latex on the ultrafine glass fibers. However, the strength of this material is weak, so it is not possible to make a large folding air filter unit (hereinafter referred to as the unit). In addition, during processing into a unit, there are breaks due to folding and breaks due to the insertion of spacers, and a clean room. It has the drawback that it is easily damaged by mishandling during installation and is easily damaged by vibration during use. On the other hand, a material prepared by preparing paper or a non-woven fabric in advance for supporting and forming an ultrafine glass fiber layer on it is disclosed as JP-A-57-35920, and such a material is produced by using a normal paper machine. It is very difficult to make paper. That is, it is very difficult to supply paper or non-woven fabric considering the structure of the paper machine, and even if it is possible, wrinkles will be generated by the operation and a fine glass fiber layer with poor water will be formed on the paper or non-woven fabric. Thickness unevenness occurs and a uniform texture cannot be obtained. As a result, the air filter using such a material has a low collection efficiency, and the uneven distribution of the material causes a rapid increase in pressure,
It has a drawback that the over-life becomes short. In addition, since such a material does not have a binder in the ultrafine glass fiber layer, there is a problem that the interlaminar strength between the material and the support layer is extremely weak and peeling in the layer is likely to occur during handling.

<Problems to be Solved by the Invention> The present inventors have earnestly studied to find a material for air filters having high strength and excellent productivity without impairing collection efficiency and pressure loss. As a result, the present invention has been achieved.

<Means for Solving Problems> That is, according to the present invention, ultrafine glass fibers 95 to 1 having a diameter of 4 μm or less are used.
00%, polyvinyl alcohol fibrous binder 5 to
0%, a fine glass fiber layer having a basis weight of 10 to 120 g / m ² , and a PVA-based fiber of 0.05 to 3 denier 80 to
100%, polyvinyl alcohol fibrous binder 2
PVA consisting of 0 to 0% and having a basis weight of 10 to 80 g / m ^2.
It is intended to provide a material for an air filter in which a compound fiber layer (hereinafter abbreviated as a compound fiber layer) made of a system fiber is combined.

The material of the present invention is composed of an ultrafine glass fiber layer and a compound fiber layer, and the ultrafine glass fiber layer is composed of ultrafine glass fibers and a polyvinyl alcohol (hereinafter referred to as PVA) -based fibrous binder, and has an ability to almost completely remove fine dust. Have,
The compound fiber layer is composed of PVA-based fiber and PVA-based fibrous binder, and is very strong because the PVA-based fiber is firmly bonded with the PVA-based fibrous binder. Both layers have the PVA-based fibrous binder. Due to the adhesive action, the layers are very strongly adhered to each other, and the interlayer strength is sufficient to withstand assembly and subsequent handling.

The ultrafine glass fiber layer of the material of the present invention comprises the ultrafine glass fiber and P
It consists of VA type fibrous binder, and it adheres between ultrafine glass fibers with almost no formation of a binder film, so dust of ultrafine glass fibers does not easily occur during use, and fine dust is almost completely removed without damaging pressure loss. In addition to being able to collect it, its power is also slightly improved. It is preferable that the ultrafine glass fiber in such a layer be 95% or more and the PVA fibrous binder be 5% or less. If the ultrafine glass fiber is less than 95%, the ability to collect fine dust is reduced, and if the PVA-based fibrous binder exceeds 5%, the pressure loss becomes large and the material life becomes short. The basis weight of such a layer is 10 to 120 g / m ² , preferably 3
0 to 90 g / m ² is preferable. If the basis weight is less than 10 g / m ² , the collection efficiency is low, and if it exceeds 120 g / m ² , the pressure loss is large.

The compound fiber layer of the present invention comprises a PVA-based fiber and a PVA-based fibrous binder, and both have a very good affinity, so that a strong paper layer is formed. Such a layer is used in combination with the ultrafine glass fiber layer to reinforce the ultrafine glass fiber layer, enable the size of the unit to be increased, and prevent damage during assembly and handling of the unit. The ratio of PVA fiber is 8
0% or more, preferably 90% or more is good, and PVA fibrous binder is 20% or less, preferably 10% or less. If the PVA fiber content is less than 80%, the amount of binder will be large, and if the content of the binder exceeds 20%, the pressure loss will be large. Basis weight is 10 to 80 g / m ² , preferably 15
-60 g / m ^{2 is} good, and if it is less than 10 g / m ² , the strength is weak and it cannot be used to reinforce the ultrafine glass fiber layer. If it exceeds 80 g / m ² , it becomes rigid and it becomes difficult to assemble it into a unit.

Also, the mixing of activated carbon fibers is effective in removing harmful gases and odors and is very preferable.

The material of the present invention is composed of an ultrafine glass fiber layer and a compound fiber layer, but each layer may be a single layer, or may be of a sandwitch structure obtained by combining compound fiber layers above and below the ultrafine glass fiber layer, among others. The latter is more preferable. In the case of the sandwitch structure, by reinforcing the ultrafine glass fiber layer from both the upper and lower sides, even if a spacer or the like comes into contact with the unit at the time of assembly, the ultrafine glass fiber layer is not exposed on the surface and is not damaged at all. The basis weight of the compound fiber layer having a sandwich structure may be such that the total of the upper and lower layers is within the range of the present invention.

The ultrafine glass fiber used in the present invention has a diameter of 4 μm or less, preferably 1 μm or less, and if it exceeds 4 μ, the collection efficiency of the obtained material decreases. Usually, ultrafine glass fibers are often an aggregate of fibers having different thicknesses, and the fiber diameter in the present invention means an average value as shown in the commercially available products.

The PVA-based fiber used in the present invention has remarkably excellent adhesiveness with the PVA-based fibrous binder, and thus contributes greatly to the improvement of the strength of the compound fiber layer. This PVA fiber may be an acetalized or non-acetalized fiber obtained from PVA as a raw material by an ordinary spinning method, and the melting temperature in water may be 90 ° C. or higher. Especially PV
Among the A fibers, those having a dissolution temperature in water of 90 to 110 ° C. adhere to each other when the wet paper made from paper is dried, are effective in improving the strength of the compound fiber layer, and also adhere to the ultrafine glass fiber layer. It is also a preferable example of the present invention because it also has the effect of increasing the interlayer strength. In addition to the PVA-based fiber, the compound fiber layer may include polyester fiber, polyacrylonitrile fiber, polyamide fiber, polypropylene fiber and the like. The fineness of the PVA fiber used is preferably 0.05 to 3 denier. If the fineness is less than 0.05 denier, the fibers are difficult to disperse, a uniform formation cannot be obtained, and the production of the fiber itself is difficult and it is not economical. If it exceeds 3 denier, the strength of the compound fiber layer is difficult to obtain. The most preferable example of the PVA fiber of the present invention has a dissolution temperature in water of 90 to 110 ° C. and a fineness of 0.
It is a PVA fiber of 1 to 0.5 denier. Do not use a binder because these fibers have excellent adhesiveness to each other,
Alternatively, even if used only slightly, it forms a strong compound fiber layer, and since it firmly adheres to the ultrafine glass fiber layer, it also has a large interlaminar strength and, in addition to these, plays an auxiliary role for the overfunction of the ultrafine glass fiber layer. In addition, it has the feature of improving overperformance.

The PVA-based fibrous binder used in the present invention is particularly effective for strongly adhering the PVA-based fibers forming the compound fiber layer firmly and strongly. The binder is a PVA having a degree of polymerization of 500 to 2500 and a degree of saponification of 85 mol% or more.
Alternatively, it is made of various modified PVA and has a dissolution temperature in water of 45 to 90 ° C., a fineness of 0.3 to 10 denier, and a fiber length of 1
It is preferably 10 mm.

As a PVA-based fibrous binder for the ultrafine glass fiber layer, the silyl-modified binder described in Japanese Patent Application No. 59-87438 is particularly effective because it has good adhesiveness to the ultrafine glass fiber, and is being used as an air filter. Very fine dust is unlikely to occur, and since a binder film is hard to form, pressure loss is unlikely to increase, and it contributes to a certain degree of strength improvement, which is very preferable. The degree of silyl modification of PVA is preferably 0.1 to 10.0 mol%.

The material of the present invention can be easily produced by a conventional wet-type papermaking machine capable of making a combination. The paper-making net used may be any of a cylinder, a short-net, a long-net, a birch former, a rotoformer, etc., and at least two or more paper-making nets for an ultrafine glass fiber layer and a compound fiber layer in a wet papermaking machine. And a process associated therewith may be used. The dryer may be a Yankee type or a multi-cylinder type.

<Effects of the Invention> The material of the present invention is composed of an ultrafine glass fiber layer and a compound fiber layer, has sufficient collection efficiency and pressure loss for use as a material for an air filter in a clean room, and is strong, so that a large unit can be produced. In addition, it has the features that damage is not likely to occur during unit assembly and subsequent handling, and that productivity is very good.

The collection efficiency in the present invention was measured according to JIS-B-9908 type 1. The pressure loss is the pressure difference measured with a JIS-L-1096 Frazier type tester at a wind speed of 4.3 cm / sec. All percentages in the present invention are weight percentages unless otherwise stated.

The present invention will be described below with reference to examples.

Example 1 A web-yankee dryer type paper machine capable of making papers,
0.5μ diameter for extra fine glass fiber layer on one cheest
Fine glass fiber 97%, fineness 1 denier, fiber length 3 m
m, a paper material consisting of 3% of a PVA-based fibrous binder (hereinafter referred to as VPB105-2 × 3) having a melting temperature of 60 ° C. in water and compounded into the other cheesto with a fineness of 1 denier for the compound fiber layer, a fiber length of 3 mm, and water PVA fiber with a melting temperature of 115 ° C (hereinafter V
97% of PK102 × 3) and VPB105-2 × 33% of paper stock are mixed, and the basis weight of the ultrafine glass fiber layer is 54.8 g.
/ M ² , and the basis weight of the compound fiber layer was 14.9 g / m ² was made into paper by a usual method.

Examples 2 to 4 By the method of Example 1, the ultrafine glass fiber layer has a diameter of 0.5 μm.
Made of 100% ultrafine glass fiber, and the basis weight is 54.2 g /
m ² with a compound fiber layer having a fineness of 0.2 denier and a fiber length of 2 m
m, PVA fiber with a melting temperature of 100 ° C in water (hereinafter VPK022
X2) and the basis weight is 16.1. g / m ²
(Example 2), the ultrafine glass fiber layer has a diameter of 0.
Made of 5% ultrafine glass fiber 97% and VPB105-2 x 3 3%, the basis weight is 13.4 g / m ² , and the compound fiber layer is VP.
K102 × 3 97%, VPB105-2 × 3 3%, a material having a basis weight of 57.2 g / m ² (Example 3), and an ultrafine glass fiber layer of 97% ultrafine glass fibers having a diameter of 0.5 μ. ,
A fibrous binder using silyl-modified PVA having a fineness of 1 denier, a fiber length of 3 mm, and a dissolution temperature of 60 ° C. in water (hereinafter SPG10
6-11 × 3) 3%, basis weight 55.2 g / m ² , compound fiber layer VPK 102 × 397%, SPG 106-11
A material (Example 4) made of 3% x 33% and having a basis weight of 16.1 g / m ² was produced.

Comparative Example 1 A normal cylinder Yankee dryer type paper machine was used to prepare a paper stock consisting of 100% ultrafine glass fibers having a diameter of 0.5 μ in a cheest, and the basis weight of a single layer was 70.6 g / m ² by a usual method. The material was made into paper.

Comparative Example 2 A paper stock consisting of 95.7% of ultrafine glass fibers having a diameter of 0.5 μm and 4.3% of acrylic latices was mixed in the cheest according to the method of Comparative Example 1, and further the acrylic latex was fixed to the ultrafine glass fibers. A material having a basis weight of 71.4 g / m ² was made into paper.

Comparative Example 3 According to the method of Example 1, the ultrafine glass fiber layer was composed of 97% ultrafine glass fibers having a diameter of 0.5 μ and VPB105 × -2 × 3 3%, the basis weight was 5.3 g / m ² , and the compound fiber layer was VPK102. × 39
7%, VPB105-2 × 3 3% and the basis weight is 60.5 g /
A material of m ² was made into paper.

The total basis weight was set to about 70 g / m ² in both the examples and comparative examples. The performance of each material is shown in Table 1.

Examples 1 to 4 are materials of the present invention comprising an ultrafine glass fiber layer and a compound fiber layer. In Example 1, the compound fiber layer was composed of PVA fiber and PVA-based fibrous binder, and had a basis weight of 14.
It is a material with a weight of 9 g / m ² , has high strength, and has sufficient collection efficiency and pressure loss to be used for an air filter. In Example 2, both layers did not use a binder, and the compounding fiber layer was a material composed only of fine denier PVA fibers having a melting temperature in water of 90 to 110 ° C. Has a strength close to that of Example 1, and the collection efficiency is almost the same, and the pressure loss is reduced. Example 3 is Example 1
This is a material in which the grammage of the compound fiber layer was increased and the grammage of the ultrafine glass fiber layer was decreased. Although the collection efficiency was slightly lower than that of Example 1, there was no problem and the strength was significantly improved.

In Example 4, instead of the binder in Example 1, SPG106-11 was used.
As compared with Example 1, the strength is slightly improved and the pressure loss is slightly reduced, but the collection efficiency is not so changed. As described above, all the materials of the present invention of Examples 1 to 4 are excellent in strength and have sufficient collection efficiency and pressure loss to be used as an air filter.

Comparative Example 1 is a single-layer material made of only ultrafine glass fibers, but its strength is very weak, so that a large unit cannot be made, and further, the unit is likely to be damaged during assembly or subsequent handling, which is not preferable. In Comparative Example 2, an acrylic latex is internally added to the material of Comparative Example 1, but the degree of reinforcement is insufficient and a large unit cannot be made. Further, the unit is easily damaged during assembly or subsequent handling. Absent. Comparative Example 3 is a material in which the basis weight of the ultrafine glass fiber layer of Example 1 is small and the collection efficiency is low, which is not preferable.

Example 5 Three tanks capable of making papermaking-Yankee dryer type paper machine with a second tee for a fine fiberglass tank having a diameter of 0.5 μ.
Prepare a paper stock consisting of 100% ultrafine glass fiber,
And VPK022 × 2 97 for the compound fiber layer in the third cheest
% VPB105-2 × 3 3% paper stock is blended to make a 3-layer laminated paper, the basis weight of the upper compound fiber layer is 7.2 g / m ² , and the basis weight of the ultrafine glass fiber layer of the middle layer is 55.2 g / m ^2, the basis weight of the lower layer of compound fiber layer has papermaking the wood of 7.6 g / m ^2. This material has tensile strength of MD 3.45kg / 15mm, CD1.57
kg / 15mm, collection efficiency 99.985%, pressure loss 25mmH ₂
O, the strength is extremely strong, the collection efficiency and the pressure loss are both sufficient for use in an air filter, and since both surfaces of the ultrafine glass fiber layer are protected by the compound fiber layer, it is easy to handle during handling. It was an excellent material that did not damage the ultrafine glass fiber layer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shosuke Higashimori 1-2-1 Kaigandori, Okayama-shi, Okayama Kuraray Co., Ltd. (72) Shoichi Nishiyama 1-2-1 Kaigan-dori, Okayama-shi, Okayama Kuraray Co., Ltd. (56) References JP-A-57-35920 (JP, A) JP-A-58-205520 (JP, A) Misao Murai, Atsushi Nakanishi "Papermaking Engineering" (39-6-10) Engineering Books Inc. P. 396 −398

Claims (12)

[Claims] 1. Ultrafine glass fibers having a diameter of 4 μm or less 95 to 100% by weight, polyvinyl alcohol fibrous binder 5 to 0
It consists of an ultrafine glass fiber layer having a basis weight of 10 to 120 g / m ² , a polyvinyl alcohol fiber of 0.05 to 3 denyl 80 to 100% by weight, and a polyvinyl alcohol fiber binder of 20 to 0% by weight. , Basis weight is 1
A material for an air filter in which PVA-based fiber layers of 0 to 80 g / m ² are combined. 2. An ultrafine glass fiber layer as a center, and PVA-based fiber layers above and below it, and the basis weight of the ultrafine glass fiber layer is 1.
The range of 0 to 120 g / m ² and the basis weight of the PVA fiber layer is 10 to 80 g / m ² for the upper and lower layers combined.
The material for an air filter according to the item. 3. The material for an air filter according to claim 1 or 2, wherein the ultrafine glass fibers have a diameter of 1 μm or less. 4. The material for an air filter according to claim 1, 1 or 2, wherein the polyvinyl alcohol fiber has a dissolution temperature in water of 90 to 110 ° C. 5. The material for an air filter according to claim 4, wherein the polyvinyl alcohol fiber having a dissolution temperature in water of 90 to 110 ° C. is 0.1 to 0.5 denier. 6. The air filter material according to any one of claims 1 to 5, wherein the polyvinyl alcohol fibrous binder comprises silyl-modified polyvinyl alcohol. 7. Ultrafine glass fibers having a diameter of 4 .mu.m or less 95 to 100% by weight, polyvinyl alcohol fibrous binders 5 to 0
It consists of an ultrafine glass fiber layer having a basis weight of 10 to 120 g / m ² , a polyvinyl alcohol fiber of 0.05 to 3 denyl 80 to 100% by weight, and a polyvinyl alcohol fiber binder of 20 to 0% by weight. , Basis weight is 1
A method for producing a material for an air filter, which comprises making a PVA-based fiber layer having a weight ratio of 0 to 80 g / m ² by sheeting. 8. A PV is provided above and below the ultrafine glass fiber layer as a center.
It has an A-based fiber layer, and the basis weight of the ultrafine glass fiber layer is 10 to 1.
The method for producing an air filter material according to claim 7, wherein the basis weight of the PVA-based fiber layer is 20 to 20 g / m ² and the upper and lower layers together are 10 to 80 g / m ² . 9. The method for producing an air filter material according to claim 7, wherein the diameter of the ultrafine glass fiber is 1 μm or less. 10. The method for producing an air filter material according to claim 7 or 8, wherein the dissolution temperature of the polyvinyl alcohol fiber in water is 90 to 110 ° C. 11. The method for producing an air filter material according to claim 10, wherein the polyvinyl alcohol fiber having a dissolution temperature in water of 90 to 110 ° C. is 0.1 to 0.5 denier. 12. The method for producing an air filter material according to any one of claims 7 to 11, wherein the polyvinyl alcohol fibrous binder is made of silyl-modified polyvinyl alcohol.