JP2020000956A - Glass filter - Google Patents

Abstract

To provide a glass filter which has high collection efficiency and has improved filter performance in the glass filter provided with a main filtration layer having a basis weight of 30 g/mor less.SOLUTION: A glass filter includes a main filtration layer which contains glass fiber as constituent fiber and has a basis weight of 30 g/mor less. Therein, the main filtration layer includes a fine glass fiber of which an average fiber diameter is 0.50 μm or less and a thick glass fiber of which an average fiber diameter is larger than that of the fine glass fiber and a percentage of mass of the fine glass fiber occupying in mass of the fine glass fiber and the thick glass fiber is larger than 40 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a glass filter.

  Traditionally, in the fields of precision industry, electronics industry, pharmaceutical industry, medical care, nursing care and welfare, and building air conditioning, dust collection equipment and dust collection equipment, home appliances and OA equipment, and transportation and transportation such as vehicles and aircraft As a filter used for air purification and dust collection, a glass filter provided with a main filtration layer containing glass fibers as constituent fibers is used. In order to provide a filter unit having a high collection rate and a low pressure loss, the glass filter provided with the main filtration layer is processed into, for example, a pleated shape and used in a frame.

  A glass filter having such a main filtration layer is required to have a high trapping rate (specifically, the trapping rate of particles having a diameter of 0.3 μm in the measurement described later is 99% or more) and a pressure drop. It is required that the filter performance be improved with a good balance (specifically, the QF value described later is improved).

As a glass filter provided with such a main filtration layer, for example, a glass filter disclosed in JP-A-10-156116 (Patent Document 1) and JP-A-2003-071219 (Patent Document 2) is known. I have. Patent Documents 1 and 2 disclose the following.
(1) If the basis weight of the glass filter is reduced, the strength physical properties are reduced. Therefore, it is advisable to reduce the pressure loss and increase the collection rate of the glass filter by devising the glass fiber composition. (Patent Document 1: 0016, Patent Document 2: 0027)
(2) Low pressure loss and high collection rate by blending two or more types of glass fibers having a large fiber diameter difference, such as an average fiber diameter of 0.55 μm or less and an average fiber diameter of 1.0 μm or more. That a glass filter can be realized. (Patent Document 1: 0017, Patent Document 2: 0028)
(3) In Examples 1 and 2 and Comparative Examples 1 to 4, a blend of 60% by weight of fine glass fibers having an average fiber diameter of 0.65 μm and 40% by weight of thick glass fibers having a diameter of 2.7 μm or more, having a basis weight of 70 g / it produced a glass filter m ^2. (Patent Document 1)
(4) In Examples 1 and 2 and Comparative Examples 1 and 2, 70% by weight of fine glass fiber having an average fiber diameter of 0.65 μm and 30% by weight of thick glass fiber having a size of 2.7 μm or more were blended. it produced a glass filter m ^2. (Patent Document 2)
(5) In Example 3, a glass filter having a basis weight of 70 g / m ² was prepared by blending 38% by weight of fine glass fibers having an average fiber diameter of 0.50 μm and 62% by weight of thick glass fibers having a size of 2.7 μm or more. thing. (Patent Document 1, Patent Document 2)

Further, since the glass filter is heavier than the organic fiber filter, the glass filter has a high collection rate (specifically, 30 g / m ² or less) and a high filter performance even though the main filtration layer is lightweight. There is also a demand for a glass filter.

JP-A-10-156116 JP 2003-071219 A

The applicants have set a benchmark of a commercially available single-layer glass nonwoven fabric filter, and have a particle collection rate of 99% or more and a higher filter performance than the filter (the QF value is the QF value of the filter). It was attempted to provide a glass filter having a lightweight main filtration layer with a basis weight of 30 g / m ² or less. However, the inventions according to Patent Literatures 1 and ² discuss an improvement in a collection rate and a QF value in a glass filter when the main filtration layer is made lightweight (specifically, 30 g / m ² or less). is not. Therefore, only by referring to the prior arts such as Patent Documents 1 and 2, the main filtration layer has a high trapping rate (specifically, 30 g / m ² or less) and a further improved QF value while being lightweight. However, it was not possible to realize a glass filter.

An object of the present invention is to provide a glass filter having a main filtration layer having a basis weight of 30 g / m ² or less, which has a high collection rate and further improved filter performance.

The problem is solved by the present invention.
[1] A glass filter comprising a main filtration layer containing glass fiber as a constituent fiber and having a basis weight of 30 g / m ² or less,
The main filtration layer contains fine glass fibers having an average fiber diameter of 0.50 μm or less, and thick glass fibers having an average fiber diameter larger than the fine glass fibers,
The percentage of the mass of the fine glass fibers in the mass of the fine glass fibers and the thick glass fibers is more than 40% by mass,
Glass filter,
[2] The problem can be solved by the glass filter of [1], which includes a flocculant.

A glass filter having a main filtration layer having a basis weight of 30 g / m ² or less has the following effects (1) and (2):
(1) Since the main filtration layer contains fine glass fibers having an average fiber diameter of 0.50 μm or less, the particle collection rate is 99% or more and the QF value (filter performance) is high (specifically, 0.1% or less). (Higher than 0313).
(2) The main filtration layer contains thick glass fibers having an average fiber diameter larger than that of the fine glass fibers, and the percentage of the mass of the fine glass fibers in the mass of the fine glass fibers and the thick glass fibers is more than 40% by mass. Therefore, a glass filter with further improved QF value (filter performance) can be realized.

  In addition, the present applicants have found that a glass filter provided with a flocculant is a glass filter in which an adhesive action by a binder is effectively exerted. Therefore, by preparing the glass filter according to the present invention using a binder, it is possible to prevent the occurrence of fibers and breakage of the fiber at the pleated peaks and valleys when the pleats are formed, and the collection rate is high. At the same time, a glass filter with improved filter performance can be provided.

《Main filtration layer》
The main filtration layer is a fabric (woven fabric, knit, nonwoven fabric, fiber web, etc.) containing fine glass fibers as constituent fibers and thick glass fibers having an average fiber diameter larger than the fine glass fibers. A nonwoven fabric in which constituent fibers are randomly entangled so that a glass filter having a high collection rate and further improved QF value can be realized, and a pleated glass filter having high flexibility can be provided. Alternatively, it is preferably a fibrous web.

  The fine glass fibers and the thick glass fibers constituting the main filtration layer can be, for example, glass fibers produced by a spinning method, a flame insertion method or a rotary method.

  In the main filtration layer, the fine glass fibers mainly contribute to the improvement of the collection rate of the filter having the filtration layer, and the thick glass fibers mainly contribute to the improvement of the QF value of the filter having the filtration layer.

  The average fiber diameter of the fine glass fibers is 0.50 μm or less so as to achieve the object of the present invention, but is preferably less than 0.50 μm because it can provide a glass filter having an excellent collection rate. .40 μm or less, and preferably less than 0.40 μm. The lower limit is appropriately adjusted, but is actually 0.1 μm or more.

  The average fiber diameter of the thick glass fibers is larger than the average fiber diameter of the fine glass fibers so that the object of the present invention can be achieved. The range of the average fiber diameter is adjusted so as to provide a glass filter having an excellent QF value, and is preferably larger than 0.50 μm and equal to or less than 1.00 μm.

The fiber diameter refers to the length of the fiber in the diameter direction in a 5000 × electron micrograph of a measurement object such as a fiber or a cloth. When the cross-sectional shape of the fiber is non-circular, the diameter of a circle having the same area as the cross-sectional area of the fiber is regarded as the fiber diameter. When the measurement is difficult because the fiber diameter is too small, the measurement may be performed based on an electron micrograph at a magnification higher than 5000 times.
The average fiber diameter of the measurement target can be obtained by selecting 800 fibers to be measured from the electron micrograph and calculating the average value of the fiber diameters measured as described above.

  The percentage of the mass of the fine glass fiber in the mass of the fine glass fiber and the thick glass fiber constituting the main filtration layer is more than 40% by mass so as to realize a glass filter having an improved collection rate of the filter, but the QF value is large. Is preferably 50% by mass or more so as to realize a glass filter with improved properties. The upper limit value of the percentage can be appropriately selected, but is realistically 90% or less so that a glass filter having a further improved QF value can be realized.

  The main filtration layer can contain fibers other than glass fibers such as cellulose fibers and organic fibers, but the constituent fibers are preferably glass fibers alone so as to achieve the object of the present invention.

  The constituent fibers of the main filtration layer are preferably bonded with a binder. In particular, it is possible to prevent the occurrence of fiber leakage and breakage at the pleated peaks and valleys when pleated, and even when a separator such as aluminum foil is inserted between the pleats, Since the breakage hardly occurs, it is possible to provide a filter and a filter unit having a high collection rate and further improved filter performance.

  The type of the binder can be appropriately selected, and examples thereof include a polyolefin (eg, a modified polyolefin), an ethylene-acrylate copolymer such as an ethylene-vinyl alcohol copolymer and an ethylene-ethyl acrylate copolymer, various rubbers and derivatives thereof [styrene-butadiene]. Rubber (SBR), fluoro rubber, urethane rubber, ethylene-propylene-diene rubber (EPDM), etc.], cellulose derivatives [carboxymethyl cellulose (CMC), hydroxyethyl cellulose, hydroxypropyl cellulose, etc.], polyvinyl alcohol (PVA), polyvinyl butyral (PVB) ), Polyvinylpyrrolidone (PVP), polyurethane, epoxy resin, polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer (PV F-HFP), an acrylic resin, a vinyl acetate resin can be used.

The solid content mass of the binder included in the main filtration layer is appropriately adjusted so that the above-described effects are effectively exerted, but may be 0.1 g / m ^{2 to} 3 g / m ² , and may be 0.3 g / m ^2. m ² can be a to 2.5 g / ^{m 2,} can be 0.5 g ^/ m 2 to 2 g / ^{m 2.} The above lower limits and upper limits can be arbitrarily combined as desired.

  The main filtration layer is, for example, a carbon material such as activated carbon or charcoal black, a flame retardant, a fragrance, a pigment (an inorganic pigment and / or an organic pigment), an antibacterial agent, an antifungal material, a photocatalyst particle, an emulsifier, a dispersant, It may contain additives such as a thickener, an antifoaming agent, a water repellent, and a surfactant. In addition, by using a binder in which an additive is mixed, a main filtration layer containing the additive can be provided.

The basis weight of the main filtration layer is 30 g / m ² or less so as to be lightweight, and the basis weight is appropriately adjusted, but it is less than 30 g / m ² so as to provide a glass filter having a lighter main filtration layer. can be, can be 25 g / ^{m 2} or less, may be less than 25 g / ^{m 2.} The lower limit is appropriately adjusted, but it is practically 1 g / m ² or more, preferably 10 g / m ² or more, and preferably 15 g / m ² or more so as to provide a glass filter having an excellent collection rate. It is preferred that These lower limits and upper limits can be arbitrarily combined as desired. In the present invention, the basis weight refers to the mass per 1 m ² of the surface (principal surface) having the largest area of the measurement object.

The thickness of the main filtration layer is appropriately adjusted, but can be 0.01 mm to 0.5 mm, can be 0.02 mm to 0.3 mm, and can be 0.04 mm to 0.2 mm. . These lower limits and upper limits can be arbitrarily combined as desired. In the present invention, the thickness refers to the length in the vertical direction when a 0.55 kgf / cm ² compressive load is applied in a direction perpendicular to the main surface.

"Base material"
The main filtration layer according to the present invention can be used alone as a glass filter,
-In order to provide a glass filter with a high collection rate and improved filter performance,
・ To provide a glass filter with high rigidity and excellent handling properties,
・ In order to prevent the occurrence of fibers and breaks in the pleated peaks and valleys when pleated,
・ Even if a separator such as aluminum foil is inserted between the pleats, the contact part between the main filtration layer and the separator is hardly damaged.
A glass filter obtained by laminating a substrate on at least one main surface of the main filtration layer is preferable, and a glass filter obtained by laminating a substrate on both surfaces is more preferable.

  In particular, in the case of a glass filter obtained by laminating a base material on both surfaces, the above-described effect is exerted on both main surfaces by making the form on both main surfaces of the filter uniform when pleated. And more preferably, the base materials provided on both main surfaces of the main filtration layer have the same configuration.

  The type of the substrate can be appropriately selected, and may be a porous film or a fabric (woven fabric, knitted fabric, nonwoven fabric, fiber web, or the like). In order to realize a glass filter having a high trapping rate and a further improved QF value, and to provide a pleated glass filter with high flexibility, the base material is composed of randomly entangled constituent fibers. It is preferably a nonwoven fabric or a fibrous web.

  The type of fiber constituting the base material can be appropriately selected. For example, polyolefin (modified polyolefin, etc.), ethylene-vinyl alcohol copolymer, ethylene-acrylate copolymer such as ethylene-ethyl acrylate copolymer, various rubbers and the like Derivatives [styrene-butadiene rubber (SBR), fluorine rubber, urethane rubber, ethylene-propylene-diene rubber (EPDM), etc.], cellulose derivatives [carboxymethyl cellulose (CMC), hydroxyethyl cellulose, hydroxypropyl cellulose, etc.], polyvinyl alcohol (PVA) , Polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), polyurethane, epoxy resin, polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer Body (PVdF-HFP), may be a glass fiber be organic fibers made of acrylic resin, vinyl acetate resin. By reinforcing and protecting the main filtration layer more effectively, the constituent fibers of the base material preferably contain glass fibers so that the above-mentioned effects are efficiently exhibited. More preferably, there is.

The configuration of the substrate is appropriately adjusted so that the above-described effects are efficiently exhibited.
Specifically, the base material is preferably a fiber layer made of fibers having an average fiber diameter larger than the constituent fibers of the main filtration layer so that the main filtration layer can be efficiently reinforced.

Further, the substrate is preferably a fabric (more preferably, a nonwoven fabric or a fibrous web) in which a fiber A having a small average fiber diameter and a fiber B having a larger average fiber diameter than the fiber are present.
The average fiber diameter of the fibers A and B is appropriately adjusted, but can be 0.5 μm to 6 μm, and the average fiber diameter of the fiber B can be 2 μm to 6 μm.
In addition, the percentage of the mass of the fiber A in the mass of the fibers A and B contained in the base material may be 1% by mass to 50% by mass, and may be 3% by mass to 45% by mass. And from 5% to 40% by weight. These lower limits and upper limits can be arbitrarily combined as desired.

  In addition, it is preferable that the base material be a mixture of chopped strands so as to provide a base material having excellent rigidity. Note that the chopped strands referred to herein are short fibers obtained by cutting spun fibers to a specific length, and fiber diameters and fiber lengths are controlled more uniformly than the glass fibers according to the present invention. Refers to In order to provide a substrate having excellent rigidity, the chopped strand is preferably a glass chopped strand.

  The average fiber diameter of the chopped strand is appropriately adjusted, but may be 2 μm to 30 μm, may be 3 μm to 25 μm, and may be 5 μm to 20 μm. These lower limits and upper limits can be arbitrarily combined as desired.

  The average fiber length of the chopped strand is appropriately adjusted, but can be 5 mm to 20 mm. In addition, it is preferable that the base material of the cloth containing the chopped strand having an average fiber length of more than 3 mm can provide a base material having higher rigidity. Therefore, the average fiber length of the chopped strand is preferably 5 mm or more. On the other hand, it is preferable that the average fiber length of the chopped strand is 20 mm or less so that the base material having higher rigidity can be provided by the uniform existence of the chopped strand.

  In addition, the percentage of the mass of the chopped strand in the constituent fibers of the base material may be 1% by mass to 50% by mass, may be 3% by mass to 45% by mass, and may be 5% by mass to 40% by mass. There can be. These lower limits and upper limits can be arbitrarily combined as desired.

It is preferable that the constituent fibers of the base material are bonded to each other with a binder, similarly to the main filtration layer. In particular, it is possible to prevent the occurrence of fiber leakage and breakage at the pleated peaks and valleys when pleated, and even when a separator such as aluminum foil is inserted between the pleats, Since the breakage hardly occurs, it is possible to provide a filter unit having a high collection rate and further improved filter performance.
Further, the base material may contain an additive similarly to the main filtration layer.

Weight per unit area of the base material is appropriately ^adjusted, but can be a ^{1g / m 2 ~100g / m 2} , can be a ^{5g / m 2 ~90g / m 2} , at 10g / ^{m 2} ~80g / m 2 There can be. These lower limits and upper limits can be arbitrarily combined as desired.

  The thickness of the base material is appropriately adjusted, but may be 0.01 mm to 1 mm, 0.03 mm to 0.7 mm, and 0.05 mm to 0.5 mm. These lower limits and upper limits can be arbitrarily combined as desired.

《Glass filter》
The configuration of the glass filter can be appropriately selected.
When the glass filter includes a main filtration layer and a base material, a binder may be provided to bond both materials.

  In particular, in the case of a glass filter containing a water repellent, when a spacer is provided by applying a molten resin on at least one main surface of the glass filter in a linear or mesh shape, the glass filter main surface and the glass filter The contact angle of the molten resin can be increased. As a result, even when the glass filter is pleated by increasing the height of the spacer, the presence of the spacer prevents the adjacent pleated peaks from contacting each other, thereby increasing the collection rate and improving the filter performance. An improved pleated glass filter can be provided, which is preferable.

  Although the type of the water repellent is appropriately selected, for example, a hydrocarbon water repellent, a fluorine water repellent, a silicone water repellent, or the like can be employed. The solid content of the water repellent contained in the glass filter is appropriately adjusted, and the solid content of the water repellent in the solid content of the binder is adjusted to be 0.1% by mass to 50% by mass. Is preferred.

  Further, if the glass filter contains a surfactant, it is possible to prevent the binder from blocking the gap between the constituent fibers of the main filtration layer and / or the base material. As a result, it is possible to provide a glass filter having a high collection rate and further improved filter performance, which is preferable.

  Although the type of the surfactant is appropriately selected, for example, a hydrocarbon-based surfactant, a fluorine-based surfactant, a silicone-based surfactant, and the like can be employed. The solid content percentage of the surfactant contained in the glass filter is appropriately adjusted, but is adjusted so that the solid content percentage of the surfactant in the solid mass of the binder is 0.01% by mass to 10% by mass. Is preferred.

  Such a glass filter provided with a water repellent and / or a surfactant can be prepared by applying a binder liquid containing a water repellent and / or a surfactant to the glass filter.

In the case of a pleated glass filter, the height of the pleated peaks, the interval between the pleated peaks, the pleat angle, and the mode of pleated folding (or corrugated folding) can be appropriately adjusted.
Also, even if a separator capable of preventing the pleats from coming into contact with each other is inserted between the pleats of the pleat filter, the molten resin is applied linearly or in a mesh form to provide spacers, so that adjacent pleats can be separated from each other. May be a filter configured to prevent contact with the filter.

  The filter having the main filtration layer according to the present invention can provide a filter unit of HEPA grade or ULPA grade.

《Manufacturing method of glass filter》
The manufacturing method of the glass filter having the main filtration layer can be appropriately selected, but the following manufacturing method can be adopted as an example.

(First method)
1. Forming a dispersion of fine glass fibers and thick glass fibers dispersed in a dispersion medium such as water on a support such as a wire and dehydrating to form a support-main filtration layer laminated structure. ,
2. A step of applying a binder liquid to the laminated structure and removing an unnecessary solvent and / or dispersion medium,
3. A process of preparing a glass filter (main filtration layer alone) by removing the support;
A method for producing a glass filter comprising:

(Second method)
1. On a support such as a wire, by forming and dehydrating a dispersion obtained by dispersing the constituent fibers of the base material in a dispersion medium such as water, a step of forming a support-base material laminated structure,
2. On the substrate-side main surface of the laminated structure, a dispersion liquid obtained by dispersing fine glass fibers and thick glass fibers in a dispersion medium such as water is formed and dehydrated, whereby the support-substrate-main filtration layer is formed. Forming a laminated structure,
3. A step of applying a binder liquid to the laminated structure and removing an unnecessary solvent and / or dispersion medium,
4. Step of preparing a glass filter having a laminated structure of the substrate-main filtration layer by removing the support,
A method for producing a glass filter comprising:

(Third method)
1. Subsequent to step 2 of the second method, the new support-substrate laminated structure prepared in step 1 of the second method is laminated on the main filtration layer side main surface of the laminated structure. -A substrate-a main filtration layer-a substrate-a step of forming a laminated structure of the support,
2. A step of applying a binder liquid to the laminated structure and removing an unnecessary solvent and / or dispersion medium,
3. Step of preparing a glass filter having a laminated structure of the substrate-main filtration layer-substrate by removing the support,
A method for producing a glass filter comprising:

(Fourth method)
1. Subsequent to the step 2 of the second method, a support is prepared by forming a dispersion obtained by dispersing the constituent fibers of the base material in a dispersion medium such as water on the main surface on the main filtration layer side of the laminated structure and dehydrating the support. -A substrate-a main filtration layer-a step of forming a laminated structure of the substrate,
2. A step of applying a binder liquid to the laminated structure and removing an unnecessary solvent and / or dispersion medium,
3. Step of preparing a glass filter having a laminated structure of the substrate-main filtration layer-substrate by removing the support,
A method for producing a glass filter comprising:

(Fifth method)
1. A step of preparing a glass filter by further laminating a substrate on the glass filter prepared by each of the above-described methods,
A method for producing a glass filter comprising:

  A flocculant may be added to the dispersion to prepare the main filtration layer and / or substrate so as to provide a main filtration layer and / or substrate to which the binder is likely to adhere. The type of the coagulant is appropriately selected, but a polyacrylate ester coagulant, a polyacrylamide coagulant, an inorganic coagulant, or the like can be employed. The proportion of the flocculant contained in the dispersion is adjusted as appropriate, and the solids concentration of the flocculant in the solids mass of the binder can be 10 ppm to 1000 ppm.

  In addition, since the binder easily adheres due to the presence of the coagulant, the main filtration layer preferably does not contain a coagulant so that the binder does not easily block the gap formed between the constituent fibers of the main filtration layer. In order to prepare the main filtration layer, it is preferable that no coagulant is added to the dispersion forming the main filtration layer during the preparation of the main filtration layer. Further, in preparing a laminated filter having a base material and a main filtration layer on at least one main surface thereof, it is preferable that only the base material layer contains an aggregating agent, in order to prepare the base material. Preferably, a coagulant is added only to the dispersion forming the substrate in the process of preparing the substrate layer. In this way, it is possible to prepare a laminated filter including the base material provided with the coagulant and the main filtration layer not provided with the coagulant on the main surface thereof. The laminated filter of this configuration is a laminated filter in which the function indicated by the presence of the above-described base material is effectively exerted by providing the base material on which the adhesive action by the binder is effectively exerted.

It is preferable to add a surfactant to the binder liquid so as to prevent a binder film from being formed between the fibers and to realize a glass filter having a further improved QF value. The ratio of the surfactant contained in the binder liquid is appropriately adjusted, but if the amount is too small, the above-mentioned effects are difficult to be exerted, and if the amount is too large, it is difficult to provide a substrate having excellent rigidity due to weak fixing of the fibers by the binder. Therefore, it is preferable to adjust so that the solid content percentage of the surfactant in the solid content mass of the binder is 0.01% by mass to 10% by mass.
Further, when a spacer is provided by applying a molten resin on at least one main surface of the glass filter in a linear or mesh shape, a repellent material is provided so that the contact angle between the glass filter main surface and the molten resin can be increased. It is preferable to use a binder liquid to which a liquid agent is added. The percentage of the solid content of the water repellent in the mass of the solid content of the binder is appropriately adjusted, and is adjusted so that the solid content of the water repellent in the mass of the solid content of the binder is 0.1% by mass to 50% by mass. Is preferred.

  The method of applying the binder liquid can be appropriately selected, and a method of spraying or applying the binder liquid by using a spray or an impregnating roll or the like, a method of immersing in the binder liquid, and the like can be adopted. Further, the binder liquid may contain a water repellent and / or a surfactant.

  The layers in the base material and the main filtration layer may be laminated and integrated by binder adhesion or fusion of adhesive fibers. Further, by subjecting the constituent fibers of the base material and the main filtration layer to entanglement and lamination and integration by subjecting them to a needle punching treatment or the like, it is also possible to further perform binder bonding and / or fusion bonding with the bonding fibers together with the entanglement. good.

  The method of removing the solvent and / or the dispersion medium can be appropriately selected, and the method is applied to natural drying, a method to a suction device, a method to dry under a reduced pressure atmosphere, and a dryer (can be heated to 100 ° C. to 200 ° C.). These methods can be used alone or in combination. The binder may be softened or dissolved by being supplied to a drier, and the constituent fibers may be bonded to each other with the binder, or may be fused with the bonded fibers.

  The glass filter prepared as described above may be bent to prepare a pleated filter. Further, a separator may be inserted between the pleated peaks. Further, a filter unit having a spacer may be formed by applying the molten resin in a linear or mesh shape.

  Further, the glass filter can be housed in a frame to form a filter unit. A conventionally known method can be employed for the shape of the frame and the method of bonding the frame to the glass filter.

  Hereinafter, the present invention will be described specifically with reference to Examples, but these do not limit the scope of the present invention.

  In the following Examples, Comparative Examples and Reference Examples, glass fibers A to E shown in Table 1 are used as constituent fibers of the main filtration layer, and glass fibers FG and glass chopped glass shown in the same table are used as constituent fibers of the base material. Strands were used. The average fiber length of the glass chopped strand is 6 mm.

(Reference Example 1)
A commercially available single-layer glass nonwoven fabric filter (basis weight: 70 g / m ² ) was prepared.

(Reference Example 2)
In 1.0 L of water, 20 parts by mass of glass fiber F, 50 parts by mass of glass fiber G, 30 parts by mass of glass chopped strand, and a polyacrylic ester-based coagulant were mixed and dispersed to prepare a slurry for preparing a base material. Prepared. The concentration of the polyacrylic ester coagulant in the slurry for preparing the base material was, in the glass filter having a laminated structure of Example 17 described below, the solid content concentration of the coagulant in the solid content mass of the binder was 250 ppm. It was adjusted to become.
By laminating and dewatering the slurry for preparing the base material on the wire, a laminated structure having the fiber web a on the wire was formed.
By supplying the laminated structure to a dryer, water as a dispersion medium was removed, and a wire was removed to prepare a glass filter (basis weight: 50 g / m ² ).

(Reference Example 3)
Glass fiber A was dispersed in 1.0 L of water to prepare a slurry for preparing a main filtration layer.
By laminating the slurry for preparing the main filtration layer on the fiber web a in the laminated structure prepared in Reference Example 2 and dewatering, the lamination structure of the fiber web derived from the wire-fiber web a-the slurry for preparing the main filtration layer was obtained. Formed.
By providing the laminated structure to a dryer, water as a dispersion medium is removed, and the wire is removed, whereby the fibrous web a (base material) -the fibrous web (main filtration layer) derived from the slurry for preparing the main filtration layer is laminated. A glass filter having a structure (basis weight: 15 g / m ² ) was prepared.

(Reference Examples 4 and 5)
Glass filter having a laminated structure in the same manner as in Reference Example 3 except that the amount of the slurry for preparing the main filtration layer to be formed on the fiber web a was changed so as to be the basis weight of the main filtration layer described in Table 2. Was prepared in various ways.

(Reference Examples 6 to 9)
The glass fiber B was used in place of the glass fiber A, and the amount of the slurry for preparing the main filtration layer prepared on the fibrous web a in the laminated structure was adjusted to be the basis weight of the main filtration layer shown in Table 2. Except for the adjustment, various types of glass filters having a laminated structure were prepared in the same manner as in Reference Example 3.

(Reference Examples 10 to 13)
The glass fiber C was used in place of the glass fiber A, and the amount of the slurry for preparing the main filtration layer prepared on the fibrous web a in the laminated structure was adjusted to the basis weight of the main filtration layer shown in Table 2. Except for the adjustment, various types of glass filters having a laminated structure were prepared in the same manner as in Reference Example 3.

(Reference Examples 14 to 17)
The glass fiber E was used in place of the glass fiber A, and the amount of the slurry for preparing the main filtration layer prepared on the fiber web a in the laminated structure was adjusted so as to be the basis weight of the main filtration layer shown in Table 2. Except for the adjustment, various types of glass filters having a laminated structure were prepared in the same manner as in Reference Example 3.

  The glass filters prepared in Reference Examples 1 to 17 were subjected to the following (evaluation method of filter performance) to obtain pressure loss (Pa), collection rate (%), and QF value of the filter, and Table 2 shows the results. Summarized.

(Evaluation method of filter performance)
The test object (glass filter) was placed in the test duct, and the collection rate (%) was calculated by a counting method. That is, after setting a planar test object (when the test object has a pleated shape, extend the bent shape to make it flat), the test object is set in a holder of a test duct having an effective frontage area of 0.04 m ² , PAO particles having a particle diameter of 0.3 μm (polyalphaolefin particles, number of PAO particles: U) are supplied to the upstream side of the test object, and the air is passed at a surface wind speed of 5.3 cm / s. The number (D) of PAO particles having a particle diameter of 0.3 μm was measured with a particle counter, and the value calculated from the following equation was defined as the collection rate (%). When the test object has a laminated structure, the test object was installed such that the fiber layer having the smallest average fiber diameter was present on the downstream side.
Collection rate (%) = [1- (D / U)] × 100

  The pressure loss (Pa) refers to the initial pressure loss (Pa) of the test object at the time of the measurement of the trapping rate.

The QF value was calculated by substituting the pressure loss (Pa) and the collection rate (%) calculated as described above into the following equation. “Ln” represents a natural logarithm.
QF value = -Ln (1-trapping rate [%] / 100) / pressure loss [Pa]

From the results in Table 2, the glass filters of Reference Examples 3 to 13 have a particle collection rate of 99% or more and a QF value (filter performance) of more than 0.0313 (the QF value of the commercially available glass nonwoven fabric filter of Reference Example 1). Although high, the glass filters of Reference Examples 14 to 17 did not satisfy the above-described performance.
As described above, in a glass filter having a main filtration layer having a basis weight of 30 g / m ² or less, the particle collection rate was 99% by being a main filtration layer containing fine glass fibers having an average fiber diameter of 0.50 μm or less. It has been found that it is possible to provide a glass filter which is excellent in the filter performance (QF value is higher than 0.0313) by more than 10%.

(Comparative Examples 1-2 and Examples 1-7)
Glass fiber A and glass fiber D or glass fiber E were mixed and dispersed in 1.0 L of water in the parts by mass shown in Table 3 to prepare a slurry for preparing a main filtration layer.
By laminating the slurry for preparing the main filtration layer on the fiber web a in the laminated structure prepared in Reference Example 2 and dewatering, the lamination structure of the fiber web derived from the wire-fiber web a-the slurry for preparing the main filtration layer was obtained. Formed.
By providing the laminated structure to a dryer, water as a dispersion medium is removed, and the wire is removed, whereby the fibrous web a (base material) -the fibrous web (main filtration layer) derived from the slurry for preparing the main filtration layer is laminated. A glass filter having a structure was prepared.

  The pressure loss (Pa), collection rate (%), and QF value of the filters prepared in Comparative Examples 1 and 2 and Examples 1 to 7 were determined, and are summarized in Table 3 together with the results of Reference Examples 3 to 5.

  From the results in Table 3, the result of comparing Reference Example 3 with Examples 1, 4, and 7, the result of comparing Reference Example 4 with Examples 2, 5, and further, the result of Reference Example 5 with Examples 3, 6 From the comparison result, the main filtration layer of the glass filter of the example contains glass fiber D or E (thick glass fiber) having an average fiber diameter larger than that of glass fiber A (fine glass fiber). It has been found that when the percentage of the mass of the fine glass fiber in the mass of the thick glass fiber is more than 40% by mass, a glass filter with further improved QF value (filter performance) can be realized.

  On the other hand, from the results of comparison between Reference Example 3 and Comparative Example 1, and between Reference Example 4 and Comparative Example 2, the main filtration layer of the glass filter of Comparative Example has a larger average fiber diameter than glass fiber A (fine glass fiber). Despite containing glass fiber D (thick glass fiber), the percentage of the mass of the fine glass fiber in the mass of the fine glass fiber and the thick glass fiber is 40% by mass or less. (Filter performance) was reduced.

  From the above, it was found that the glass filter having the main filtration layer having the configuration of the present invention can provide a glass filter having a high collection rate and further improved filter performance.

(Examples 8 to 16)
Glass fiber A and glass fiber D were mixed and dispersed in 1.0 L of water in the parts by mass shown in Table 4 to prepare a slurry for preparing a main filtration layer.
By laminating the slurry for preparing the main filtration layer on the wire and dewatering, a laminated structure in which the fiber web constituting the filtration layer was deposited on the wire was formed.
By supplying the laminated structure to a dryer, water as a dispersion medium was removed, and a wire was removed to prepare a glass filter composed of only a fiber web constituting a filtration layer.

  The pressure loss (Pa), collection rate (%), and QF value of the glass filters prepared in Examples 8 to 16 were determined and summarized in Table 4.

From the results in Table 3, it can be seen that, according to the present invention, in a glass filter having a main filtration layer having a basis weight of 30 g / m ² or less, the particle collection rate is 99% or more and the filter performance is excellent (QF value is less than 0.0313). (High) glass filter could be provided.

(Example 17)
Glass fiber A and glass fiber D were mixed and dispersed in 1.0 L of water in parts by mass shown in Table 5 to prepare a slurry for preparing a main filtration layer.
By laminating the slurry for preparing the main filtration layer on the fiber web a in the laminated structure prepared in Reference Example 2 and dewatering, the lamination structure of the fiber web derived from the wire-fiber web a-the slurry for preparing the main filtration layer was obtained. Formed.
In the prepared laminated structure, the laminated structure prepared in Reference Example 2 was newly laminated on the main surface of the fiber web derived from the slurry for preparing the main filtration layer, and a wire-fiber web a-for preparing the main filtration layer A slurry fibrous web-fibrous web a-wire laminated structure was formed.
Next, a binder liquid containing a vinyl acetate resin binder dispersion liquid (dispersion medium: water), a fluorine water repellent, and a fluorine surfactant was prepared.
After immersing the laminated structure in the binder liquid, the lifted laminated structure is subjected to a dryer to remove water as a dispersion medium, and the wire is removed to remove the fibrous web a (substrate) -main filtration layer. A glass filter having a laminated structure of fiber web (main filtration layer) -fiber web a (substrate) derived from the slurry for preparation was prepared.
The constituent fibers of the glass filter were bonded with a binder. Table 5 shows the proportion of the vinyl acetate resin binder, the polyacrylate ester coagulant (contained only in the base material), the fluorine water repellent, and the fluorine surfactant in the solid content of the binder. As described.

(Examples 18 to 25)
Percentage of vinyl acetate resin binder, polyacrylate ester coagulant (contained only in the base material), fluorine water repellent, and fluorine surfactant in the solid content of the binder contained in the glass filter Was adjusted as shown in Table 5, and a glass filter having a laminated structure was prepared in the same manner as in Example 17.

From the results in Table 5, it is understood that, according to the present invention, a glass filter having a main filtration layer with a basis weight of 30 g / m ² or less has a particle collection rate of 99% or more and is excellent in filter performance (QF value is less than 0.0313). (High) glass filter could be provided.

  Further, the glass filters of Examples 17 to 25 in which the base materials having the same configuration were provided on both main surfaces of the filtration layer had high rigidity and excellent handleability.

Then, the glass filters of Examples 17 to 25 were provided to a pleating machine to give pleated shapes.
・ Pleated mountain height: 60mm
・ The interval between pleats: 4mm
The thus prepared glass filter processed into a pleated shape did not suffer from fiber sprinkling or breakage at the pleated peaks and valleys. In addition, the folds between Pleated Mountain and Pleated Valley were sharp.

  Further, an aluminum foil was inserted as a separator between the pleated peaks of the pleated glass filter, and then placed in a frame-shaped frame. Then, a filter unit was prepared by integrating the contact portion between the filter and the frame with a urethane resin binder. In the glass filter in the filter unit prepared in this way, no breakage occurred in the contact portion between the glass filter and the aluminum foil.

  The glass filter of the present invention can be used, for example, in the fields of precision industry, electronics industry, pharmaceutical industry, medical care, nursing care and welfare, and building air conditioning, dust collection equipment and dust collection equipment, home appliances and OA equipment, vehicles and aircraft, etc. It can be used as a filter used for air purification and dust collection in the field of transportation.

Claims (2)

A glass filter comprising a main filtration layer containing a glass fiber as a constituent fiber and having a basis weight of 30 g / m ² or less,
The main filtration layer contains fine glass fibers having an average fiber diameter of 0.50 μm or less, and thick glass fibers having an average fiber diameter larger than the fine glass fibers,
The percentage of the mass of the fine glass fibers in the mass of the fine glass fibers and the thick glass fibers is more than 40% by mass,
Glass filter.   The glass filter according to claim 1, further comprising a flocculant.