JPH0246249B2 - FUIRUTAAOYOBISONOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to the structure of a filter and its manufacturing method, and is particularly suitable as a bag filter for dust collection. Traditionally, woven fabrics and non-woven fabrics have been widely used as bag filters. These filters primarily filter the dust adhering to the filter using the primary layer, and the nonwoven fabric filter also has a filtration function inside the filter, and has high dust collection efficiency. In addition, for these filters, the surface is burnt to eliminate fuzz, or the surface of the non-woven fabric is coated with
It is also possible to use low-melting point fibers or core-sheath type composite fibers consisting of a low-melting point skin part and a high-melting point skeleton part, and to melt the surface and give it a mirror finish to improve the releasability of dust. However, in these filters,
At the beginning of use or immediately after dust is brushed off, the primary layer of dust has not been formed, and until this is formed, the filtration efficiency is low and sufficient filtration cannot be performed. In recent years, as the performance of bag filters has improved, there has been an increasing demand for filters that have low pressure loss, high dust collection efficiency, and good dust removal properties. In response to such demands, a filter has been proposed in which a porous resin layer having air permeability is formed on the surface of a reinforcing material made of woven or nonwoven fabric. A filter with this structure filters most of the dust on the surface of the porous resin layer without waiting for the primary layer of dust to form, so it has excellent performance at the beginning of use or immediately after dust is removed. It has a large dust collection effect. Prior Art A filter with the above structure is one in which a porous tetrafluoroethylene polymer layer having a continuous pore structure is formed on the surface of a reinforcing material (Japanese Patent Laid-Open No. 52-80579).
(No. 164179), a reinforcing material in which a foamed resin layer with residual air bubbles is formed on the surface of the felt (Utility Model Application Publication No. 164179/1983), and a reinforcing material with micropores containing conductive filler on the surface. One in which a countless number of foamed resin layers are formed (Japanese Patent Application Laid-open No. 64612/1983) is known. Problems to be Solved by the Invention This type of filter filters dust on the surface of the porous resin layer, so it reduces air resistance and pressure loss.
Further, in order to reduce clogging due to dust, the thickness of the porous resin layer is preferably as thin as possible. However, if the thickness of the porous resin layer is thin, the porous resin layer will be easily worn out, torn, or peeled off due to surface abrasion caused by dust, and the fluff on the surface of the nonwoven fabric will protrude from the surface of the porous resin layer. , the dust removability is poor. In the case of the product disclosed in JP-A No. 52-80579, the tetrafluoroethylene polymer used for the porous resin layer itself has poor adhesiveness and lacks adhesiveness with the reinforcing material. , the wear resistance was low. In addition, Utility Model Application Publication No. 164179/1982
In the structure shown in Japanese Patent No. 64612, it is extremely difficult to set the thickness of the porous resin layer. That is, as described above, when the thickness of the porous resin layer is large, air resistance becomes large, pressure loss becomes large, and clogging due to dust is likely to occur. On the other hand, if it is thin, fluff will protrude from the surface of the porous resin layer, resulting in poor dust releasability, and the porous resin layer will easily peel off or tear from the reinforcing material surface due to wear, resulting in poor durability. It becomes. The present invention was made in view of the above circumstances, and an object of the present invention is to provide a filter that has a small pressure loss, is hard to cause clogging, has a porous resin layer that has excellent abrasion resistance, and has excellent durability. It is something to do. Means for Solving the Problems The filter of the present invention has a first nonwoven fabric having a basis weight of 10 g/m ² or more on one side of the woven fabric, and a second nonwoven fabric having a basis weight of 150 g/m ² or more on the other side. , solid content weight 10 to 10 on the first nonwoven fabric of the reinforcing material formed by stacking them and applying needle punching from both sides.
Form a first foamed resin layer of 50 g/m ² on the first foamed resin layer using a resin with better surface releasability than the resin that forms the first foamed resin layer. Forming a second foamed resin layer of ~100g/ ^m2 ,
It is characterized in that the sum of the thicknesses of the first foamed resin layer and the second foamed resin layer is 0.2 mm or less. The structure of the filter of the present invention will be explained below with reference to the drawings. The drawing shows a filter according to the invention. 1 is a reinforcing material, and a first nonwoven fabric 3 is stacked on one side of a woven fabric 2, and a second nonwoven fabric 4 is stacked on the other side, and needle punches are applied from both sides. The woven fabric 2 is a woven fabric made of synthetic fibers such as polyester, polyethylene, polypropylene, nylon, polyacrylonitrile, aromatic polyamide, etc., and its structure includes plain weave, twill weave,
Sateen weave or other appropriate structures can be used. Like the woven fabric 2, the first nonwoven fabric 3 and the second nonwoven fabric 4 are made of synthetic fibers such as polyester, polyethylene, polypropylene, nylon, polyacrylonitrile, aromatic polyamide, etc., and are short or long fiber nonwoven fabrics. can do. The basis weight of these nonwoven fabrics is 10 for the first nonwoven fabric 3.
g/m ² or more, and the second nonwoven fabric 4 should be 150 g/m ² or more. Air permeability, tensile strength, tear strength of reinforcement material 1,
Regarding mechanical performance such as dimensional stability, the optimum value varies depending on the type of dust and the conditions in which the filter is used, but for a general bug filter, the air permeability is 10 c.c./cm ² / sec or more (JIS-L-
1096, Frazier type method, same hereafter. ), tensile strength is over 50kgf/5cm width (strip method), tear strength is over 20kgf (same, trapezoid method),
Regarding dimensional stability, it is desirable that the tensile load at 5% elongation is 15 kgf/5 cm width or more. In this reinforcing material 1, a surface filtration layer 5 is formed on the first nonwoven fabric 3. The surface filtration layer 5 includes a first foamed resin layer 6 formed on the first nonwoven fabric 3 and a second foamed resin layer 7 formed on the first foamed resin layer 6. It has two layers. The resin constituting the surface filtration layer 5 may be an acrylic synthetic resin or rubber that has relatively high rubber elasticity and can form an emulsion, or a copolymer thereof, in terms of heat resistance and foamability. is suitable. An optimal example thereof is methyl methacrylate-acrylic acid ester copolymer. Other styrene-butadiene-based, polyester-based, polyurethane-based, polyamide-based resins or rubbers, or copolymers thereof may also be used as long as they can form an emulsion. The first foamed resin layer 6 and the second foamed resin layer 7
Although different resins can be used, from the viewpoint of adhesiveness, it is preferable to use resins of the same type as the main components. As the first foamed resin layer 6,
A resin having a glass transition temperature lower than room temperature and having adhesive properties is desirable. Further, the second foamed resin layer 7 uses a resin having better surface releasability than the first foamed resin layer 6. As such a resin, a resin that is the same type of resin as the resin and has a glass transition temperature higher than room temperature is added as an anti-adhesive agent to the resin constituting the first foamed resin layer 6 having adhesive properties. Those with reduced tackiness are preferred. For example, when using the methyl methacrylate-acrylic acid ester copolymer as the foamed resin, the first foamed resin layer 6 is made of a material with a glass transition temperature of about -17°C, and the second foamed resin layer 6 is made of a material with a glass transition temperature of about -17°C. The resin layer 7 has a glass transition temperature of -17
The glass transition temperature of 70 to 95% by weight of the resin is around ℃.
A resin containing 5 to 30% by weight of resin at about 50°C is used. Furthermore, in place of the resin having a high glass transition temperature, inorganic additives such as silica and talc, emulsions, oils, powders, etc. of fluorine-based or silicon-based resins may be added as anti-blocking agents. The coating amount of the first foamed resin layer 6 is preferably 10 to 50 g/m ² in terms of solid weight, and the resin amount of the second foamed resin layer 7 is preferably 20 to 100 g/m 2 .
g/m ² is appropriate. Also, the surface filtration layer 5
The total thickness is preferably 0.2 mm or less.
If the amount of resin in the surface filtration layer 5 is too small, the fuzz of the reinforcing material 1 will protrude from the surface, making it difficult to obtain a smooth surface and resulting in poor dust releasability. Moreover, if the amount of resin is too large, air resistance becomes large and pressure loss becomes large, which is not preferable. The pore size of the second foamed resin layer 7 in the surface filtration layer 5 should be set according to the particle size of the target dust, but generally for bag filters,
Approximately 10 to 20 μm is appropriate. The pore diameter of the first foamed resin layer 6 is preferably the same as or larger than the pore diameter of the second foamed resin layer 7. If the pore diameter of the first foamed resin layer 6 is small, the boundary between the first foamed resin layer 6 and the second foamed resin layer 7 will be clogged with dust, and it will be difficult to release the dust, which is not preferable. . The air permeability of the surface filtration layer 5 in the filter of the present invention is suitably about 10 to 25 c.c./cm ² /sec. Next, in the method for manufacturing a filter of the present invention, a first nonwoven fabric having a basis weight of 10 g/m ² or more is placed on one side of the woven fabric,
A second nonwoven fabric with a basis weight of 150 g/m ² or more is stacked on the other side, needle punched from both sides to form a reinforcing material, and a foaming resin liquid is solidified on the first nonwoven fabric in the reinforcing material. Minute weight 10-50g/
^m2 , and after solidifying the foamable resin liquid, it is pressed with a hot roll to lay down the fuzz on the surface of the first nonwoven fabric to form a first foamed resin layer, and then the foamable resin liquid is A foaming resin liquid, which has better mold releasability than the resin liquid, is applied to a release paper at a solid content of 20 to 100 g/ ^m2 , and is pressed onto the first foamed resin layer without solidifying. This is characterized in that the release paper is removed after solidifying this to form a second foamed resin layer. To explain the present invention step by step, first, as a first step, a first nonwoven fabric 3 having a basis weight of 10 g/m ^{2 or more is applied to one side of the woven fabric 2, and a first nonwoven fabric 3 having a basis weight of 150 g/m 2} or more is applied to the other side.
The second nonwoven fabrics 4 of m ² or more are stacked on top of each other,
Needle punched from both sides to create an integrated reinforcing material 1
form. Next, as a second step, a curing agent, a curing catalyst, a foam stabilizer, and a thickener are blended into the resin in an emulsion state that can be mechanically foamed, and the resulting foamed composition is mechanically foamed using an oak mixer or the like. on the first nonwoven fabric 3 of the reinforcing material 1, with a solid content of 10 to 50
Coat at a ratio of g/m ² and dry. The foaming ratio of the foaming composition is 3 depending on the pore size and the strength of the resin layer.
~5 times is appropriate. After drying, the surface of the foamed resin is crimped with a suitable hot roll, the fuzz on the surface of the first nonwoven fabric 3 is laid down, and the first foamed resin layer 6 is formed. Next, as a third step, a curing agent, a curing catalyst, a foam stabilizer, and a thickener are blended into the resin in an emulsion state that can be mechanically foamed, and an anti-blocking agent is further added to perform mechanical foaming. The appropriate expansion ratio is about 3 to 5 times. The obtained foamed composition is applied onto a release paper so that the solid content is 20 to 100 g/m ² , and is pressed onto the surface of the first foamed resin layer 6 in an undried state. The magnitude of the pressing force is preferably such that the foam of the foam composition is not crushed, and is preferably 1 kgf/cm or less. After pressure bonding, the temperature is gradually raised to dry and harden, and the release paper is removed. Thereby, the second foamed resin layer 7 is formed on the surface of the first foamed resin layer 6. Function In the filter of the present invention, since the surface filtration layer 5 is composed of two layers, the first foamed resin layer 6 and the second foamed resin layer 7, the fluff on the surface of the reinforcing material 1 is removed from the first foamed resin layer. 6 and does not protrude through the second foamed resin layer 7. Therefore, the surface of the filter is smooth and has excellent dust releasability, and even if the surface filtration layer 5 is slightly worn, fluff will not protrude. Also, the second foamed resin layer 7
has better releasability than the first foamed resin layer 6, so the first foamed resin layer 6 can firmly adhere to the reinforcing material 1, and the second foamed resin layer 7 Forms a surface with excellent releasability against dust. Therefore, when filtering dust with the filter of the present invention, most of the dust is captured in the surface filtration layer 5, and a small amount of the dust that has passed through the surface filtration layer 5 is captured inside the first nonwoven fabric 3. Ru. Since the thickness of the surface filtration layer 5 is extremely thin, 0.2 mm or less, the inside of the surface filtration layer 5 is not clogged with dust. In addition, the basis weight of the first nonwoven fabric 3 is 10
g/m ² or more, the dust that has passed through the surface filtration layer 5 can be reliably captured within the first nonwoven fabric 3, and the dust can reach the boundary between the woven fabric 2 and the first nonwoven fabric 3. This will not cause the fabric 2 to become clogged. Further, since the surface of the surface filtration layer 5 is made of the second foamed resin layer 7 which has excellent mold releasability, if dust is accumulated on the surface of the filter, it can be easily brushed off. In addition, the second nonwoven fabric 4 in the reinforcing material 1 ensures the thickness of the filter, as well as mechanical strength, and functions to prevent damage caused by flanges, retainers, etc. when the filter of the present invention is attached. . In addition, in the method of the present invention, the first foamed resin layer 6 is formed on the reinforcing material 1, and the top is pressed with a hot roll to lay down the fuzz, so that the surface of the first nonwoven fabric 3 in the reinforcing material 1 is The fuzz is embedded in the first foamed resin 6 as described above, and hardly penetrates into the second foamed resin layer 7. Furthermore, the second foamed resin layer 7 is applied to a release paper and is pressed onto the surface of the first foamed resin layer 6 in an undried state, so that the surface filtration layer 5 has a small amount of resin and a small thickness. Also, extremely smooth surfaces can be formed. Effects of the Invention According to the filter of the present invention, the surface filtration layer 5 is formed on the surface of the filter, and since dust is filtered by the surface filtration layer 5, it is necessary to wait until the primary layer of dust is formed. It is possible to effectively capture dust even at the beginning of use and immediately after dust is brushed off, and the dust collection efficiency is high. Further, as mentioned above, the fluff of the reinforcing material 1 is embedded in the first foamed resin 6, and the second foamed resin layer 7 is formed on top of it, so that the surface filtration layer 5 is sufficiently thin. Even if the surface filtration layer 5 is worn out, fluff will not protrude and the dust releasability will not be hindered. Therefore, in the filter of the present invention, the surface filtration layer 5 has a sufficiently thin thickness of 0.2 mm or less, resulting in low pressure loss, and has a smooth surface with excellent dust removability and durability. It is excellent. Further, according to the method of the present invention, the first foamed resin layer 6 is applied to the reinforcing material 1, dried, and then pressed with a hot roll, and then the second foamed resin layer 7 applied to release paper is applied on top of the first foamed resin layer 6. Since the pressure bonding is carried out in a dry state, it is possible to form a thin and smooth surface filtration layer 5 with excellent abrasion resistance. Examples Examples of the present invention will be described below and compared and discussed with comparative examples. Example 30.5 x 31.5 250d polyester filament yarns were placed on a polyester spunbond nonwoven fabric with a basis weight of 84g/ ^m2 as the first nonwoven fabric 3.
Layer the woven fabric 2 woven in a plain weave with inch, and on top of that, the second non-woven fabric 4 with a basis weight of 210
A reinforcing material 1 was formed by stacking polyester spunbond nonwoven fabrics of g/m ² and needle punching from both upper and lower sides at a total density of 250 pieces/cm ² . Methyl methacrylate-acrylic acid ester copolymer emulsion (Rezamin AEX-320, manufactured by Dainichiseika Chemical Co., Ltd., glass transition temperature approximately -17°C,
To 100 parts by weight (solid content concentration 55% by weight), 10 parts by weight of melamine as a curing agent, 1 part by weight of organic acid amine as a curing catalyst, further 7 parts by weight of ammonium stearate as a foaming agent, and 7 parts by weight of ammonium stearate as a thickener. Two parts by weight of sodium polyacrylate were added and mixed to prepare a mixed solution A having a solid content concentration of 54% by weight. In addition, as an anti-adhesive agent in the mixed liquid A,
Methyl methacrylate-acrylic acid ester copolymer emulsion (manufactured by Chuo Rika Kogyo Co., Ltd.)
ES-251, glass transition temperature approximately 50℃, solid content concentration 48
% by weight) to prepare a mixed solution B having a solid content concentration of 54% by weight. Next, the mixed liquid A is mechanically foamed using an oak mixer to form a foamed composition with a foaming ratio of about 3 times, and this is placed on the first foamed resin layer 6 of the reinforcing material 1 at a rate of 60 g/m ² (solid content: 32 g/m ² ). Next, this was dried by heating at 120°C for 2 minutes, and then heated with a heated roll at 110°C to smooth the coated surface. Next, the mixture B was foamed three times in the same way, and this foamed composition was applied to a release paper at 100 g/m ² (solid content 54 g/m ² ), and in an undried state, the reinforcing material 1
It was layered on the coated surface of the first foamed resin layer 6 in .
This was crimped with a calendar roll at 0.5Kg/cm,
It was dried by heating in three stages: 70°C for 1 minute, 100°C for 1 minute, and 120°C for 1 minute, and further heated at 150°C for 2 minutes to harden the resin, and then the release paper was removed. The thickness of the surface filtration layer 5 of the obtained filter is:
The average pore diameter was about 20 μ, and the air permeability of the filter as a whole was 20 c.c./cm ² /sec. Comparative Example 1 On the first nonwoven fabric 3 of the same reinforcing material 1 as described in the example, 160 g/m ² (solid content 86 g/m ² ) of a foaming composition prepared from mixed solution B was applied, dried,
A filter was obtained by curing. Comparative Example 2 On the first nonwoven fabric 3 of the same reinforcing material 1 as described in Example, 300 g/m ² (solid content 162 g/m ² ) of a foaming composition prepared from mixed liquid B was applied, dried,
A filter was obtained by curing. Comparative Example 3 A polyester short fiber nonwoven fabric with a basis weight of 150 g/m ² was layered on both sides of the same woven fabric 2 as in Example 2, and a reinforcing material was added by needle punching from both sides at a total density of 250 fibers/cm ² . Formed. On one side of this reinforcing material, polyurethane adhesive is applied in dots, and a porous polytetrafluoroethylene polymer film with a thickness of 0.1 mm and a pore diameter of approximately 5 μm is placed on top of it.
A filter was obtained by laminating by calendering. Test Method Pressure Loss A filter with a diameter of 90 mm is attached to a glass flange with a filtration inner diameter of 60 mm and a filtration area of 28.3 ^cm2 , and the sides of the filter are sealed. JIS-Z with mixer
- While crushing the 11th class dust of 8901, the filtration air speed is 3.
The pulverized dust is sucked at a rate of m/min, and the pressure difference between the dust-containing air side and the clean air side is defined as a pressure loss, and the pressure loss is 80 mmaq., 120 mmaq., and 150 mmaq.
The amount of dust deposited on the filter surface was measured. Surface abrasion property: According to JIS-L-1084 A-2 flat method,
Polishing was performed using AA-180 abrasive paper under a load of 200 g, and the number of times until the surface filtration layer 5 was torn was measured. Further, the surface filtration layer 5 was polished using CC-400CW abrasive paper under a load of 1 lb according to the plane method of the universal method of JIS-L-1096, and the number of times until the surface filtration layer 5 was torn was measured. Tensile strength Measured by the strip method of JIS-L-1096. Load at 5% elongation The test piece was pulled according to the strip method of JIS-L-1096, and the load when the test piece was elongated by 5% was measured. Tear strength Measured by the trapezoid method of JIS-L-1096. Test results The test results are shown in the table.

[Table] As is clear from the results, Comparative Example 1 without the adhesive layer formed by the first foamed resin layer 6 and Comparative Example 3 in which the tetrafluoroethylene polymer layer was formed have better wear resistance than the Examples. It can be seen that the quality is significantly inferior. In addition, Comparative Example 2 in which a thick surface filtration layer 5 was formed,
It can be seen that the pressure loss and its increase due to dust accumulation are larger than those of the example. Observing the cross sections of the filters of Example and Comparative Example 2 after long-term filtration, it is found that in Example, the dust that passed through the thin surface filtration layer 5 was transferred to the first nonwoven fabric 3.
However, in the case of the filter of Comparative Example 2, the thick surface filtration layer 5 was clogged. Furthermore, it can be seen that the examples of the present invention have sufficient mechanical strength and dimensional stability in terms of tensile strength, load at 5% elongation, tear strength, etc.

[Brief explanation of drawings]

The drawing is a sectional view of the filter of the present invention. DESCRIPTION OF SYMBOLS 1... Reinforcement material, 2... Woven fabric, 3... First nonwoven fabric, 4... Second nonwoven fabric, 5... Surface filtration layer, 6
...First foam resin layer, 7...Second foam resin layer.

Claims (1)

[Claims] 1. A first non-woven fabric 3 having a basis weight of 10 g/m ² or more is layered on one side of the woven fabric 2, and a second non-woven fabric 4 having a basis weight of 150 g/m ² or more is stacked on the other side, A first foamed resin layer 6 having a solid content weight of 10 to 50 g/m ² is formed on the first nonwoven fabric 3 of the reinforcing material 1 formed by needle punching from both sides, and the first foamed resin layer 6 is A solid content of 20 to 100 is made of a resin having better surface releasability than the resin forming the first foamed resin layer 6 thereon.
g/m ² of the second foamed resin layer 7, and the sum of the thicknesses of the first foamed resin layer 6 and the second foamed resin layer 7 is 0.2 mm or less, filter. 2. The resin forming the first foamed resin layer 6 is
The resin forming the second foamed resin layer 7 is mainly composed of a methyl methacrylate-acrylic acid ester copolymer having a glass transition point lower than room temperature.
70 to 95% by weight of a methyl methacrylate-acrylic ester copolymer whose glass transition temperature is lower than room temperature, and 5 to 95% by weight of a methyl methacrylate-acrylic ester copolymer whose glass transition temperature is higher than room temperature.
2. A filter according to claim 1, characterized in that the main component is a mixture of 30% by weight. 3 A first nonwoven fabric 3 with a basis weight of 10 g/m ² or more is layered on one side of the woven fabric 2, and a second nonwoven fabric 4 with a basis weight of 150 g/m ² or more is layered on the other side, and reinforced by needle punching from both sides. forming a reinforcing material 1;
A foamable resin liquid is applied onto the first nonwoven fabric 3 at a solid content of 10 to 50 g/m ² ,
After the foamable resin liquid is solidified, it is pressed with a hot roll to lay down the fuzz on the surface of the first nonwoven fabric 3 to form a first foamed resin layer 6, which has a mold releasability better than that of the foamable resin liquid. Apply a good foaming resin liquid to the release paper so that the solid content is 20 to 100 g/ ^m2 ,
A method for manufacturing a filter, which comprises pressing the first foamed resin layer 6 in an unsolidified state, solidifying it to form the second foamed resin layer 7, and then removing the release paper.