JP5098740B2 - Method for producing glass fiber fabric for bag filter - Google Patents

Description

  The present invention relates to a manufacturing method for manufacturing a glass fiber fabric for bag filters.

Glass fiber fabrics are used as dust collecting bag filters for garbage incinerators and steel furnaces. As a conventional glass fiber fabric for bag filters, for example, as described in Patent Document 1, a glass fiber fabric is coated with a composition containing silicone resin, graphite, and tetrafluoroethylene resin. It has been.
JP-A-6-39220

  Since the bag filter is provided at the exhaust port of the various furnaces described above, the glass fiber fabric used for the bag filter is always used under pressure. Therefore, the glass fiber fabric is required to have a tensile strength that can withstand this pressure. Further, the bag filter is used for a certain period while performing maintenance for separating dust by performing so-called back washing or the like periodically. In this backwash, the glass fiber fabric is repeatedly bent. Accordingly, the glass fiber fabric is required to have folding resistance that can resist this repeated bending. Such a bag filter is always exposed to a high temperature and acidic environment, and the glass fiber fabric is replaced at regular intervals in preparation for breakage due to a decrease in tensile strength and folding resistance. Therefore, in order to make the replacement period as long as possible for the purpose of cost reduction, it is difficult for the glass fiber fabric for the bag filter to deteriorate in strength and folding resistance in a high temperature and acidic environment. Required. In this respect, the conventional glass fiber fabric lacks acid resistance and heat resistance, and it is difficult to maintain sufficient strength and folding resistance.

  The present invention has been made in view of the above problems, and is excellent in acid resistance and heat resistance, and is not easily deteriorated in tensile strength and folding resistance even under high temperature and acidic environments. It aims at providing the manufacturing method which manufactures.

The manufacturing method of the glass fiber fabric for bag filters which concerns on this invention heat-processes a glass fiber fabric, and when the mass of the said glass fiber fabric is 100 mass%, the mass of the size agent which remains in the said glass fiber fabric A deoiling step of 0.3% by mass or less, a resin coating step of coating a glass fiber fabric with a resin composition containing a tetrafluoroethylene resin (hereinafter referred to as PTFE), graphite and a silicone resin, and a resin composition A drying step of drying the glass fiber fabric coated with the material at a temperature of 120 ° C. or more and 250 ° C. or less , and the mass ratio of the tetrafluoroethylene resin, the graphite and the silicone resin contained in the resin composition is 1 : 0.2 to 0.5: 0.05 to 1.0 .

According to the method for producing a glass fiber fabric for bag filter of the present invention, the sizing agent adhering to the glass fiber fabric is removed, and the ratio to the mass of the glass fiber fabric becomes 0.3% by mass or less. It is possible to prevent the bending resistance of the glass fiber fabric from being deteriorated in a high temperature environment. When the sizing agent adhering to the glass fiber fabric exceeds 0.3% by mass, the folding resistance tends to deteriorate under a high temperature environment. In addition, since the glass fiber fabric is coated with a resin composition containing PTFE, graphite, and silicone resin, it is possible to obtain a glass fiber fabric for a bag filter that hardly deteriorates in strength and folding resistance even in a high temperature and acidic environment. . Since PTFE contributes to the hardness of the glass fiber fabric for bag filters, the glass fiber fabric coated with a resin composition not containing PTFE lacks folding resistance. Further, since the silicone resin contributes to the improvement of the tensile strength, the glass fiber fabric covered with the resin composition not containing the silicone resin lacks the tensile strength. Furthermore, since the resin composition is dried at a low temperature of 250 ° C. or less, the glass fiber fabric and the resin composition are prevented from being deteriorated by heat during drying, and the tensile strength and folding resistance are deteriorated even in a high temperature environment. A glass fiber fabric for a bag filter that is difficult to obtain can be obtained.
Further, when the mass ratio of the silicone resin when the mass of PTFE is 1 is less than 0.05, the tensile strength and the folding resistance tend to be deteriorated under a high temperature environment. In addition, when the mass ratio of the silicone resin exceeds 1.0, the mass of PTFE becomes relatively small, so that the folding resistance tends to deteriorate under a high temperature environment. By setting the mass ratio of the silicone resin in which PTFE is 1 to 0.05 to 1.0, it is possible to obtain a glass fiber fabric for a bag filter that has extremely low deterioration in strength and folding resistance in a high temperature environment. Moreover, since the mass ratio of the graphite which made PTFE 1 was 0.2-0.5, deterioration of the folding resistance of the glass fiber fabric for bag filters in a high temperature environment is prevented.

  Moreover, in the manufacturing method of the glass fiber fabric for bag filters which concerns on this invention, it is preferable that the heat processing of a deoiling process are performed at the temperature of 350-650 degreeC, and the time for 30 seconds or less. By heating at a temperature of 350 ° C. or higher, the proportion of the mass of the sizing agent remaining in the glass fiber fabric can be made 0.3 mass% or less with respect to the mass of the glass fiber fabric. When heated at a temperature of less than 350 ° C., the sizing agent remaining on the glass fiber fabric cannot be removed sufficiently. By heating at a temperature of 650 ° C. or lower and a time of 30 seconds or shorter, a decrease in strength of the glass fiber fabric can be prevented.

  Moreover, the manufacturing method of the glass fiber fabric for bag filters which concerns on this invention has further the process of attaching potassium nitrate aqueous solution to a glass fiber fabric before a deoiling process, It is characterized by the above-mentioned. Since potassium nitrate acts as an oxidizing agent, by attaching potassium nitrate to the glass fiber fabric, the sizing agent can be easily pyrolyzed, and thermal deterioration of the glass fiber in the desulfurization process can be suppressed.

In the manufacturing method of a glass fiber textile bag filter according to the present invention, the glass fiber fabric is made of acid-resistant glass, the acid resistance _{glass, SiO 2, Al 2 O 3} , CaO, MgO, B 2 O 3, And R ₂ O (R is Na or K) as a component, and the content of each component when the total mass of the acid-resistant glass is 100% by mass is 55 to 60% by mass of SiO ₂ , Al ₂ O ₃ is 10 to 14% by mass, CaO and MgO are 20 to 28% by mass in total, B ₂ O ₃ is preferably 1% by mass or less, and R ₂ O is preferably 1% by mass or less. In the method for producing a glass fiber fabric for a bag filter according to the present invention, since a glass fiber fabric composed of a glass fiber bundle of acid resistant glass containing the above components is used, strength and folding resistance are not easily deteriorated even in an acidic environment. A glass fiber fabric for bag filters is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the manufacturing method which manufactures the glass fiber fabric for bag filters which is excellent in acid resistance and heat resistance, and is hard to deteriorate tensile strength and folding resistance also in a high temperature and acidic environment. It becomes.

  Hereinafter, with reference to drawings, the embodiment of the manufacturing method of the glass fiber fabric for bag filters concerning the present invention is described in detail. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a view showing a part of a glass fiber fabric for bag filter produced by the production method according to this embodiment. The glass fiber fabric 1 for bag filter includes a glass fiber fabric 10 and a resin coating layer 15. The glass fiber fabric 10 is covered with a resin coating layer 15.

The glass fiber fabric 10 is obtained by plain weaving warps 12 and wefts 14. The weaving method is not limited to plain weaving, and for example, double weaving, satin weaving, twill weaving and the like are employed. The thickness of the glass fiber fabric 10 is preferably 0.2 to 1.0 mm, for example. Moreover, it is preferable that the mass per unit area of the glass fiber fabric 10 is 250-950 g / m < ² >, for example.

  One of the warp yarn 12 and the weft yarn 14 is made of a filament yarn, and the other is a bulky yarn. These yarns are made of a glass fiber bundle, and the count of the glass fiber bundle is preferably 60 to 360 tex, for example. The count (tex) of the glass fiber bundle corresponds to the mass (gram number) per 1000 m of the glass fiber. It is preferable that the nominal diameter of the glass fiber which comprises a glass fiber bundle is 7 micrometers or less. When the nominal diameter is larger than 7 μm, the folding resistance of the glass fiber fabric 10 is lowered.

Although the composition of the glass used for the glass fiber of the glass fiber fabric 10 is not specifically limited, For example, E glass is used. Further, acid resistant glass is preferably used. The composition of E glass and acid resistant glass is shown in Table 1. The acid resistant glass contains SiO ₂ , Al ₂ O ₃ , CaO and MgO as components. Also, acid resistance _glass, B 2 _{O 3} and _R 2 O (R is Na or K) can be included as components. The content of each component with respect to the total mass of the acid resistance glass, SiO ₂ is 55-60 wt%, _Al 2 _{O 3} is 10 to 14 wt%, 20 to 28 wt%, the total of CaO and MgO, _{B 2} O ₃ is 1% by mass or less and R ₂ O is 1% by mass or less. By using the acid-resistant glass having such a composition, it is possible to obtain the glass fiber fabric 1 for a bag filter that hardly deteriorates in tensile strength and folding resistance even in an acidic environment.

  The resin coating layer 15 is a layer formed to cover the warp yarns 12 and the weft yarns 14 of the glass fiber fabric 10 by impregnating the glass fiber fabric 10 with a resin composition and solidifying the resin composition. The dust contained in the exhaust from various furnaces is collected in the resin coating layer 15, and the gas in the exhaust passes through the gap between the warp 12 and the weft 14, so that the glass fiber fabric 1 for bag filter is used as a bag filter. Demonstrate the function.

  The resin composition used for forming the resin coating layer 15 includes PTFE, graphite, and silicone resin. Since PTFE contributes to the hardness of the resin coating layer 15, the glass fiber fabric 1 for bag filters excellent in folding resistance can be obtained by including PTFE in the resin composition. Since the silicone resin contributes to the improvement of the tensile strength of the resin coating layer 15, the bag fiberglass fiber fabric 1 having excellent tensile strength can be obtained by including the silicone resin in the resin composition. Furthermore, the mass ratio of PTFE, graphite and silicone resin contained in the resin composition is preferably 1: 0.2 to 0.5: 0.05 to 1.0. By setting the mass ratio of graphite when PTFE is 1 to 0.2 to 0.5, the folding resistance of the glass fiber fabric 1 for bag filter can be improved. When the mass ratio of graphite when PTFE is set to 1 is less than 0.2 or exceeds 0.5, folding resistance is lowered. Moreover, by setting the mass ratio of the silicone resin when PTFE is 1 to 0.05 or more, it is possible to obtain a glass fiber fabric 1 for a bag filter that hardly deteriorates in tensile strength and folding resistance in a high temperature environment. it can. In addition, by setting the mass ratio of the silicone resin to 1 or less when PTFE is 1, it is possible to obtain the glass fiber fabric 1 for a bag filter that is unlikely to deteriorate its folding resistance in a high temperature environment. Further, setting the mass ratio of the silicone resin having PTFE of 1 to 1 or less contributes to maintaining the hardness necessary for processing such as sewing. When the mass ratio of the silicone resin when the mass of PTFE is 1 is less than 0.05, the tensile strength and folding resistance tend to deteriorate in a high temperature environment, and the mass ratio of the silicone resin is If it exceeds 1.0, the mass of PTFE becomes relatively small, and therefore the folding resistance tends to deteriorate under a high temperature environment.

  The mass of the resin coating layer 15 is preferably 5 to 20% by mass when the mass of the glass fiber fabric 1 for bag filter is 100% by mass. When the proportion of the mass of the silicone resin contained in the resin coating layer 15 is increased in order to improve the tensile strength, the proportion of the mass of PTFE is relatively decreased. Since PTFE contributes to the hardness of the resin coating layer 15, the glass fiber fabric for bag filter 1 covered with the resin coating layer 15 with little PTFE lacks folding resistance. By setting the mass of the resin coating layer 15 to 5 to 20% by mass, the glass fiber fabric 10 is coated with a sufficient amount of PTFE, so that the folding resistance is not easily deteriorated even in a high temperature and acidic environment. Glass fiber fabric 1 can be obtained.

  Next, the manufacturing method for manufacturing the glass fiber fabric 1 for bag filters is demonstrated.

  First, the glass fiber fabric 10 is heat-treated, and the sizing agent adhering to the glass fiber fabric is removed. The sizing agent is a sizing agent for bundling glass fibers to form a glass fiber bundle, and is made of, for example, a starch-based material. When the glass fiber fabric 10 in which the sizing agent remains is coated with the resin coating layer 15 to produce the glass fiber fabric 1 for bag filter, the sizing agent is deteriorated by heat, and the resin coating layer 15 is bonded to the glass fiber fabric 10. It causes peeling. The resin coating layer 15 peeled from the glass fiber fabric 10 does not exhibit performance such as heat resistance. In addition, the glass fiber fabric 10 used here consists of E glass, for example. It is more preferable to use a glass fiber fabric made of acid-resistant glass. By using acid-resistant glass, it is possible to obtain a glass fiber fabric 1 for a bag filter that hardly deteriorates in tensile strength and folding resistance even in an acidic environment.

  The mass of the sizing agent remaining in the glass fiber fabric 10 by this heat treatment is preferably 0.3% by mass or less with respect to the mass of the glass fiber fabric. By setting the mass of the remaining sizing agent to 0.3% by mass or less, the adhesion between the resin coating layer 15 and the glass fiber fabric 10 is maintained, and the folding resistance of the glass fiber fabric for bag filter 1 in a high temperature environment is maintained. Deterioration can be prevented.

  Moreover, it is preferable that this heat processing is performed at the temperature of 350-650 degreeC, and time for 30 seconds or less. By heating at a temperature of 350 ° C. or higher, the proportion of the mass of the sizing agent remaining in the glass fiber fabric can be made 0.3 mass% or less with respect to the mass of the glass fiber fabric. When heated at less than 350 ° C., the sizing agent remaining on the glass fiber fabric cannot be removed sufficiently. By heating at a temperature of 650 ° C. or lower and a time of 30 seconds or shorter, a decrease in strength of the glass fiber fabric 10 can be prevented. Although depending on the heating temperature, the heating time is preferably 10 seconds or longer in order to reduce the remaining sizing agent.

  Furthermore, it is also preferable to apply potassium nitrate to the glass fiber fabric 10 before the heat treatment. Since potassium nitrate acts as an oxidizing agent, the sizing agent is easily decomposed by heat treatment by applying potassium nitrate.

  Next, the glass fiber fabric 10 is coated with the resin coating layer 15 by impregnating and solidifying the glass fiber fabric 10 with the resin composition.

  Specifically, first, the glass fiber fabric 10 is impregnated with a solution composed of a resin composition containing PTFE, graphite, and silicone resin. Examples of the method for impregnating the solution include a method of immersing the glass fiber fabric 10 in the solution, a method of applying the solution to the glass fiber fabric, and the like. The mass ratio of PTFE, graphite and silicone resin contained in the resin composition is preferably 1: 0.2 to 0.5: 0.05 to 1.0. By setting the resin composition to the above-mentioned composition, it is possible to obtain the glass fiber fabric 1 for a bag filter in which tensile strength and folding resistance are hardly deteriorated under a high temperature environment. Moreover, in order to obtain the glass fiber fabric 1 for bag filters in which folding resistance is hard to deteriorate, the mass ratio of the silicone resin with PTFE being 1 is more preferably 0.5 to 0.8.

  Next, the glass fiber fabric 10 impregnated with the solution is dried at a temperature of 250 ° C. or lower. By drying at a temperature of 250 ° C. or lower, generation of fine cracks in the glass fiber and thermal decomposition of the silicone resin are prevented. By this drying, the resin composition is solidified, and the resin coating layer 15 is formed so as to cover the warp yarns 12 and the weft yarns 14 of the glass fiber fabric 10. In order to solidify the resin composition efficiently, it is preferable to dry within 3 minutes at a temperature of 120 ° C. or higher. The glass fiber fabric 1 for bag filters is obtained by the process described above.

  Hereinafter, preferred examples of the present invention will be described, but the present invention is not limited to the following examples.

Example 1
[Production of glass fiber fabric]
A glass fiber woven fabric was produced using a double woven fabric method using a glass fiber bundle composed of glass fibers of E glass having the composition shown in Table 1 as warp and weft. The warp yarn was a 135 tex filament yarn, and the density at the time of weaving was 48 yarns / 25 mm. The wefts were 270 tex bulky yarns, and the density when woven was 48/25 mm. The nominal diameter of the glass fiber was 6 μm. This glass fiber fabric was dipped in a 3.6% by mass potassium nitrate solution and dried to allow potassium nitrate to adhere to the glass fiber fabric, and further heated at a temperature of 590 ° C. for 20 seconds to remove the sizing agent. By this heat treatment, the ratio of the mass of the sizing agent to the mass of the glass fiber fabric was 0.20% by mass.

[Preparation of resin coating layer]
First, a treatment liquid containing a resin composition was prepared. The treatment liquid is a mixed liquid composed of a PTFE 60% liquid, a graphite 20% liquid, and a silicone resin 35% liquid. Here, the “% solution” indicates the proportion of the mass of the solute contained in the solution. For the PTFE solution, it is preferable to use a dispersion having a molecular weight of 2,000,000 to 10,000,000 and a particle size of 0.15 to 0.35 μm. Here, polyflon (trade name) manufactured by Daikin Industries, Ltd. was used. . As the graphite solution, it is preferable to use a natural graphite dispersion dispersion. Here, Coroheite (trade name) manufactured by Nippon Graphite Industry Co., Ltd. was used. It is preferable to use phenylmethyl silicone for the silicone resin solution, and here, a silicone resin manufactured by Toray Dow Corning Co., Ltd. was used. By appropriately adjusting the mass of each solution to be blended, a treatment liquid was prepared in which the mass ratio of PTFE, graphite, and silicone resin solute was 1: 0.3: 0.6. This treatment liquid was impregnated into a glass fiber fabric and dried at a temperature of 190 ° C. for 3 minutes to form a resin coating layer to obtain a glass fiber fabric for bag filter. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 8.89% by mass.

(Example 2)
A glass fiber fabric for a bag filter was obtained in the same manner as in Example 1 except that the drying temperature after impregnating the glass fiber fabric with the treatment liquid was 160 ° C. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 8.91% by mass.

(Example 3)
A glass fiber woven fabric for bag filters was obtained in the same manner as in Example 1 except that acid-resistant glass shown in Table 1 was used instead of E glass as the glass constituting the glass fiber woven fabric. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 8.54% by mass.

(Comparative Example 1)
A glass fiber fabric for bag filters was obtained in the same manner as in Example 1 except that the heat treatment for removing the sizing agent adhering to the glass fiber fabric was not performed. The ratio of the mass of the sizing agent to the mass of the glass fiber fabric was 0.69% by mass, and the ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 9.47% by mass.

(Comparative Example 2)
A glass fiber fabric for bag filter was obtained in the same manner as in Example 1 except that the drying temperature after impregnating the glass fiber fabric with the treatment liquid was 260 ° C. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 9.45% by mass.

Example 4
A glass fiber fabric for a bag filter was obtained in the same manner as in Example 1 except that the mass ratio of PTFE, graphite, and silicone resin in the treatment liquid was 1: 0.15: 0.6. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 9.19% by mass.

(Example 5)
A glass fiber fabric for a bag filter was obtained in the same manner as in Example 1 except that the mass ratio of PTFE, graphite and silicone resin in the treatment liquid was 1: 0.6: 0.6. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 12.36% by mass.

(Example 6)
A glass fiber fabric for a bag filter was obtained in the same manner as in Example 1 except that the mass ratio of PTFE, graphite and silicone resin in the treatment liquid was 1: 0.3: 0.3. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 8.31% by mass.

(Example 7)
A glass fiber fabric for a bag filter was obtained in the same manner as in Example 1 except that the mass ratio of PTFE, graphite and silicone resin in the treatment liquid was 1: 0.3: 1.2. The ratio of the mass of the resin coating layer to the mass of the glass fiber fabric was 12.40% by mass.

Table 2 shows the production conditions of the bag filter glass fiber fabric in the above Examples and Comparative Examples. About the size agent and the resin coating layer, the ratio of the mass with respect to the mass of a glass fiber fabric was shown.

[Evaluation of glass fiber fabric for bag filter]
About the glass fiber fabric for bag filters of each of Examples 1 to 7 and Comparative Examples 1 and 2, a tensile test and a folding test were performed in each of normal conditions, acid immersion, and heat exposure. The test results are shown in Table 3. In the normal state, after being manufactured by the above-described manufacturing method, the test is performed in a state where no particular load is applied. Acid dipping is carried out after each sample piece of glass fiber fabric for bag filter is dipped in a 10% by mass sulfuric acid aqueous solution and left at room temperature for 72 hours, followed by washing with water and drying at 110 ° C., respectively. The degree of deterioration of the glass fiber fabric for bag filter in an acidic environment can be evaluated by a test under the conditions of acid immersion. In the heat exposure, each test is performed after heating the sample piece in an oven at an ambient temperature of 250 ° C. for 100 hours.

  In the tensile test, a sample piece having a width of 25 mm was held and held at an interval of 150 mm, the sample piece was stretched at a speed of 200 mm / min, and the maximum tensile load at the time of breaking the test piece was measured. These conditions comply with JIS R3420 type III.

In the folding test, the sample piece was held at a spacing of 55 mm with a 15 mm width, the sample piece was bent at 270 degrees per minute, and the number of reciprocal bending until the sample piece was broken was measured. These conditions are based on JIS R3420.

The folding endurance in heat exposure of Example 1 was superior to the same test result of Comparative Example 1. Further, the folding endurance in heat exposure of Example 1 was superior to the test result of Comparative Example 2.
The test result of Example 2 was almost the same as that of Example 1.

  The tensile strength and folding resistance in acid immersion of Example 3 were extremely superior to the test results of Example 1. In addition, the folding endurance in the normal state and heat exposure of Example 3 was superior to the test result of Example 1.

  The folding endurance in the normal state and heat exposure of Example 1 was significantly superior to the results of the same tests of Example 4 and Example 5. The folding endurance in the normal state and heat exposure of Example 1 was remarkably superior to the results of the same tests of Example 6 and Example 7.

  Example 1 and Example 2 were superior to Comparative Example 1 and Comparative Example 2 in heat resistance, and it was confirmed that folding resistance was not easily deteriorated even in a high temperature environment. In addition, Example 3 was superior to Example 1 in acid resistance and heat resistance, and it was confirmed that tensile strength and folding resistance were not easily deteriorated even under high temperature and acidic environment. Example 3 is particularly excellent in acid resistance. Furthermore, Example 1 was superior to Examples 4-7 in heat resistance, and it was confirmed that folding resistance is hard to deteriorate also in a high temperature environment.

It is a figure which cuts out and shows a part of glass fiber fabric for bag filters concerning an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass fiber fabric for bag filters, 10 ... Glass fiber fabric, 12 ... Warp, 14 ... Weft, 15 ... Resin coating layer.

Claims (4)

A manufacturing method for manufacturing glass fiber fabrics for bag filters,
A deoiling step of heat-treating the glass fiber fabric and setting the mass of the sizing agent remaining in the glass fiber fabric to 0.3% by mass or less when the mass of the glass fiber fabric is 100% by mass;
A resin coating step of coating the glass fiber fabric with a resin composition containing tetrafluoroethylene resin, graphite, and silicone resin;
Drying the glass fiber fabric coated with the resin composition at a temperature of 120 ° C. or higher and 250 ° C. or lower ; and
The bag filter glass , wherein the mass ratio of the tetrafluoroethylene resin, graphite and silicone resin contained in the resin composition is 1: 0.2 to 0.5: 0.05 to 1.0 A method for producing a textile fabric.   The method for producing a glass fiber fabric for a bag filter according to claim 1, wherein the heat treatment in the deoiling step is performed at a temperature of 350 to 650 ° C and a time of 30 seconds or less.   The method for producing a glass fiber fabric for bag filter according to claim 1 or 2, further comprising a step of attaching an aqueous potassium nitrate solution to the glass fiber fabric before the deoiling step. The glass fiber fabric is made of acid-resistant glass,
The acid-resistant glass contains SiO2, Al2O3, CaO, MgO, B2O3, and R2O (R is Na or K) as components, and the content of each component when the total mass of the acid-resistant glass is 100% by mass. Is characterized in that SiO2 is 55 to 60 mass%, Al2O3 is 10 to 14 mass%, CaO and MgO are 20 to 28 mass% in total, B2O3 is 1 mass% or less and R2O is 1 mass% or less. The manufacturing method of the glass fiber fabric for bag filters of any one of Claims 1-3 to do.

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