JP5451993B2 - Inorganic fiber paper and honeycomb structure and filter using the same - Google Patents

Description

  The present invention relates to an inorganic fiber paper, a honeycomb structure using the same, and a filter, and more particularly to an inorganic fiber paper containing rock wool as a main fiber.

Conventionally, in view of the problem regarding the carcinogenicity of ceramic fibers, for example, Patent Document 1 describes a nonwoven fabric using biosoluble fibers and a honeycomb structure using the same.
Japanese Patent Laid-Open No. 2003-105662

  On the other hand, the inventors of the present invention have independently developed inorganic fiber paper that uses other inorganic fibers as main fibers and has a low environmental load. However, for example, it has not been easy to produce an inorganic fiber paper that has characteristics suitable for corrugating and has sufficient strength even after firing when a honeycomb structure is formed.

  The present invention has been made in view of the above problems, and provides an inorganic fiber paper that has a low environmental load and is suitable for a honeycomb structure, and a honeycomb structure and a filter using the same. One of the purposes.

  An inorganic fiber paper according to an embodiment of the present invention for solving the above-mentioned problems has a thickness of 500 μm or less, contains rock wool as a main fiber, and further contains glass fibers. ADVANTAGE OF THE INVENTION According to this invention, the inorganic fiber paper with a small environmental load and suitable for a honeycomb structure can be provided.

  Moreover, the said glass fiber is good also as the average fiber diameter being in the range of 3-10 micrometers. In this way, the inorganic fiber paper can have characteristics more suitable for the honeycomb structure. In this case, the glass fiber may have an average fiber length in the range of 3 to 15 mm. In this way, the inorganic fiber paper can have characteristics more suitable for a honeycomb structure. In these cases, the inorganic fibers constituting the inorganic fiber paper contain the rock wool in the range of 60 to 90% by weight and the glass fiber in the range of 10 to 40% by weight. It is good. In this way, the inorganic fiber paper can have characteristics particularly suitable for a honeycomb structure.

Moreover, the said inorganic fiber paper is good also as the US basis weight being in the range of 5-500 g / m < ² >. In this way, the inorganic fiber paper can have characteristics suitable for corrugating and forming a honeycomb structure. The rock wool may have a shot content of 212 μm or more in diameter of 2% by weight or less and a shot content of less than 212 μm in diameter of 20% by weight or less. In this way, the inorganic fiber paper can have characteristics more suitable for corrugating and forming a honeycomb structure.

  A honeycomb structure according to an embodiment of the present invention for solving the above-described problems has any one of the above-described inorganic fiber papers corrugated. According to the present invention, it is possible to provide a honeycomb structure having a small environmental load and sufficient strength.

  Further, the honeycomb structure may be fired. In this way, the honeycomb structure can have characteristics suitable for use at high temperatures. Further, the honeycomb structure may carry a functional agent. By so doing, the honeycomb structure can have a function corresponding to the type of the functional agent.

  A filter according to an embodiment of the present invention for solving the above-described problems has the honeycomb structure on which a functional agent is supported. According to the present invention, it is possible to provide a filter that has a low environmental load and sufficient strength.

  Hereinafter, an embodiment of the present invention will be described. Note that the present invention is not limited to this embodiment. The inorganic fiber paper (hereinafter referred to as “the present paper”) according to the present embodiment has a thickness of 500 μm or less, contains rock wool as a main fiber, and further contains glass fibers.

  The thickness of the paper is not particularly limited as long as it is not less than a predetermined value necessary for maintaining its shape and not more than 500 μm, but can be, for example, in the range of 10 to 500 μm, preferably It can be in the range of 20 to 500 μm, more preferably in the range of 50 to 500 μm, and particularly preferably in the range of 100 to 500 μm.

  This paper contains rock wool and glass fiber, and can have characteristics suitable for corrugating and forming a honeycomb structure when the thickness is within the above range. That is, in this case, the present paper can have a fine corrugated shape corresponding to the shape of the corrugator without being broken, for example, by corrugating. In addition, for example, a honeycomb structure formed from the present paper can have sufficient strength to maintain its shape, and can have a large surface area suitable for supporting a functional agent.

  Rock wool, which is the main material of inorganic fibers constituting this paper, is an inorganic fiber mainly composed of silicon oxide and calcium oxide. For example, rock wool is made from blast furnace slag separated from pig iron at the time of pig iron production or natural rocks such as basalt, and fiberized molten slag melted at a high temperature of 1500 to 1600 ° C by a cupola or electric furnace. Can be manufactured.

  Rock wool has the property of being moderately degraded in nature. For this reason, by using rock wool as the main material of the inorganic fibers constituting the paper, the environmental load of the paper can be effectively reduced compared to ceramics.

  As the rock wool, for example, those having an average fiber diameter (average diameter of one fiber) in the range of 1 to 10 μm can be used, and those having an average fiber diameter in the range of 2 to 4 μm are preferably used. Can do.

  Moreover, as rock wool, what has a small content rate of a shot and a thing with a small diameter of the contained shot can be used preferably. Specifically, as rock wool, for example, a material having a shot content of 212 μm or more in diameter of 2% by weight or less and a shot content of less than 212 μm in diameter of 20% by weight or less can be preferably used. More preferably, the content of shots with a diameter of 212 μm or more is 1% by weight or less, and the content of shots with a diameter of less than 212 μm is 15% by weight or less, and the content of shots with a diameter of 212 μm or more Is 0.5% by weight or less and the content of shots having a diameter of less than 212 μm is 10% by weight or less can be particularly preferably used. The shot content can be measured, for example, by a method based on JIS R3311 using a sieve having a nominal size of 212 μm of JIS Z8801.

  When the shot content of rock wool (particularly, rock wool contained in the paper) is within the above range, the formability of the paper in corrugating can be effectively enhanced. That is, in this case, for example, in corrugation processing for imparting a corrugated shape to the paper, formation of holes and scratches due to dropping of the shot in the paper, reduction in strength of the paper, and collision between the shot and the corrugator It is possible to effectively avoid problems such as damage to the corrugator. As a result, the honeycomb structure having the corrugated paper as a part of the skeleton can have sufficient strength to maintain the shape.

  Moreover, as rock wool, the rock wool manufactured using the electric furnace can be used preferably. That is, for example, while performing melting at a high temperature using an electric furnace, the average fiber diameter is fiberized by high-speed spinning, the average fiber diameter is within the preferred range, and the shot content is the above Rock wool that is within a suitable range can be preferably used. Moreover, the rock wool to which the process for reducing a shot content rate (deshot process) was performed after fiberization can also be used.

  By including glass fibers in addition to rock wool, the present paper can have properties suitable for corrugating and forming a honeycomb structure while being an inorganic fiber paper having a thickness of 500 μm or less.

  That is, for example, in inorganic fiber paper that has been used for the formation of honeycomb structures in the past, by simply replacing the main fibers from ceramic fibers to rock wool, characteristics suitable for corrugating and honeycomb structure formation are achieved. Difficult to do.

  The glass fiber contained in the paper can be used without particular limitation as long as it can improve the properties of the paper so as to be suitable for corrugating and forming a honeycomb structure.

  Specifically, as the glass fiber, for example, those having an average fiber diameter in the range of 3 to 10 μm can be preferably used. In this case, glass fibers having an average fiber diameter of less than 10 μm can be used more preferably. That is, for example, glass fibers having an average fiber diameter in the range of 3 to 9 μm can be more preferably used, and glass fibers having an average fiber diameter in the range of 5 to 7 μm can be particularly preferably used. In addition, the average fiber diameter of glass fiber can be measured as an average thickness of a fiber by the method based on JISA9504, for example.

  When the average fiber diameter of the glass fiber is within the above range, this paper contains rock wool as the main fiber and has a thickness of 500 μm or less, and is suitable for corrugating and forming a honeycomb structure. Can have.

  That is, in this case, for example, the paper can have a sufficient strength that does not break even when tension is applied during corrugating. In addition, for example, a honeycomb structure formed of the corrugated paper can have sufficient strength to maintain its three-dimensional shape even after firing.

  In addition, in the inorganic fiber paper whose main fiber is rock wool having a relatively low strength and the thickness is 500 μm or less, when the average fiber diameter of the glass fibers contained exceeds 10 μm, for example, the glass fibers For example, it may be difficult to impart sufficient strength to the inorganic fiber paper due to insufficient entanglement. Moreover, when the average fiber diameter of glass fiber is less than 3 micrometers, the effect of reinforcement by the said glass fiber becomes inadequate, for example, and it may become difficult to provide sufficient intensity | strength to inorganic fiber paper.

  Moreover, as glass fiber, in addition to the average fiber diameter being in the above range, those having an average fiber length (average length of one fiber) in the range of 3 to 15 mm are preferable. Can be used. That is, as the glass fiber, for example, those having an average fiber diameter in the range of 3 to 10 μm and an average fiber length in the range of 3 to 15 mm can be preferably used, and the average fiber diameter is 3 to 9 μm. And an average fiber length in the range of 4 to 10 mm can be more preferably used, an average fiber diameter in the range of 5 to 7 μm and an average fiber length of 5 to 7 mm. Those within the range can be particularly preferably used. In addition, the average fiber length of glass fiber can be measured by analyzing the microscope picture of glass fiber with an image analyzer, for example.

  When the average fiber diameter of the glass fiber is within the above range and the average fiber length of the glass fiber is within the above range, the paper has characteristics particularly suitable for corrugating and forming a honeycomb structure. Can have.

  That is, in this case, for example, it is possible to reliably have sufficient strength that does not break even when tension is applied during corrugating. For example, the honeycomb structure formed by the corrugated paper can reliably have sufficient strength to maintain the three-dimensional shape even after firing.

  Even if the average fiber diameter of the glass fibers is within the above-mentioned preferable range, inconvenience may occur when the average fiber length of the glass fibers exceeds 15 mm. That is, in this case, for example, in the wet papermaking slurry containing rock wool and glass fiber, the glass fiber is not appropriately dispersed, and thus it becomes difficult to produce an inorganic fiber paper having a thickness of 500 μm or less. obtain. Further, even if the average fiber diameter of the glass fiber is within the above preferred range, when the average fiber length of the glass fiber is less than 3 mm, for example, the effect of reinforcement by the glass fiber becomes insufficient, and the inorganic fiber It may be difficult to give the paper strength suitable for corrugating or forming a honeycomb structure.

  Moreover, it is preferable that the inorganic fiber which comprises this paper contains rock wool within the range of 60 to 90 weight%, and contains glass fiber within the range of 10 to 40 weight%. Further, in this case, the inorganic fiber constituting the paper preferably contains rock wool in the range of 65 to 85% by weight and more preferably glass fiber in the range of 15 to 35% by weight. It is particularly preferable that the glass fiber is contained within a range of 20 to 30% by weight.

  When the proportions of rock wool and glass fiber in the inorganic fibers contained in this paper are within the above ranges, this paper has a low environmental burden and has heat resistance, while corrugated or honeycomb structure. It can have properties suitable for body formation.

  In this case, the properties of the paper are further improved when the average fiber diameter of the glass fibers contained in the paper is within the preferred range. In particular, when the average fiber diameter and the average fiber length of the glass fibers are within the above-mentioned preferable ranges, the properties of the paper are extremely excellent.

In addition to the thinness of 500 μm or less, the paper preferably has a predetermined density. That is, the present paper, preferably has a basis weight (weight per 1 m ²⁾ is in the range of 5 to 500 g / ^{m 2,} more preferably in the range of 10 to 300 g / ^{m 2,.} 15 to Particularly preferably, it is within the range of 150 g / m ² . In addition, the rice tsubo can be measured, for example, by a method for measuring the basis weight of paper and board according to JIS P8124. When the paper weight of the paper is within the above range, the paper can have characteristics suitable for corrugating and forming a honeycomb structure.

  Moreover, this paper can also contain inorganic fibers other than rock wool and glass fiber. As such other inorganic fibers, for example, alumina fibers, mullite fibers, carbon fibers, and metal fibers can be used.

  However, the total of the proportion of rock wool and the proportion of glass fiber in the inorganic fibers contained in the paper is preferably 50% by weight or more, more preferably 60% by weight or more, and 75% by weight. The above is particularly preferable. When the sum of the proportion of rock wool and the proportion of glass fiber is within the above range, the paper can surely have excellent characteristics based on the above-mentioned rock wool and glass fiber.

  Moreover, this paper can also contain an organic fiber in addition to an inorganic fiber. As the organic fiber, for example, pulp, polyvinyl alcohol fiber, polyethylene terephthalate (PET) fiber, and acrylic fiber can be used. The paper can also contain a binder. Examples of the binder that can be used include inorganic binders such as silica sol, alumina sol, and titania sol, and organic binders such as acrylic resin, phenol resin, and epoxy resin. As these organic fibers and binders, for example, those suitable for producing this paper by a wet papermaking method can be appropriately selected and used.

  However, the paper preferably contains 30% by weight or more of inorganic fibers after firing, more preferably 50% by weight or more, and particularly preferably 70% by weight or more. That is, the present paper can be reduced in content of organic components such as organic fibers and binders by firing. For example, the organic components such as organic fibers and binders are substantially removed by firing, It can also be set as the paper which consists of inorganic fiber which does not contain the said organic component. When the content of the inorganic fiber is in the above range, the paper can have an appropriate strength even after firing, for example.

  Moreover, as this paper, what was manufactured by the wet papermaking can be used preferably. That is, in this case, in the method for producing the paper, first, a slurry containing mainly rock wool as inorganic fiber and further containing glass fiber is prepared. This slurry can contain an organic fiber and a binder as needed. And this paper can be manufactured from this slurry as a nonwoven fabric whose thickness is 500 micrometers or less from this slurry by the wet papermaking method using a predetermined paper machine.

  The honeycomb structure according to the present embodiment (hereinafter referred to as “the present structure”) has the corrugated paper. That is, the present structure has a honeycomb-shaped skeleton including the corrugated paper.

  FIG. 1 is a perspective view of a honeycomb structure 1 which is an example of the present structure, and FIG. 2 is a cross-sectional view of the honeycomb structure 1. As shown in FIGS. 1 and 2, the honeycomb structure 1 includes a corrugated corrugated main paper (hereinafter referred to as “corrugated paper 10”) and an uncorrugated flat main paper (hereinafter referred to as corrugated paper). And “a flat paper 20”).

  That is, the honeycomb structure 1 is configured by sandwiching one corrugated paper 10 between a pair of opposed flat papers 20a and 20b. The corrugated paper 10 has a plurality of cells 11 that are continuously connected and formed by corrugating.

  The curved shape of the cell 11 corresponds to the shape of the corrugator used for manufacturing the corrugated paper 10. That is, for example, when the corrugated paper 10 is manufactured using a pair of gear-like corrugators that rotate while meshing with each other, the cell 11 has a shape corresponding to the tooth shape of the gear.

  Here, it is preferable that the shape of the cell 11 is closer to a perfect circle. Therefore, in corrugating the inorganic fiber paper, for example, a gear-shaped corrugator whose tooth tip shape is close to a perfect circle is used. However, when a conventional inorganic fiber paper (ceramic paper) containing ceramic fibers as the main fiber is corrugated using such a corrugator, the shape of the cells of the ceramic paper is a perfect circle such as a triangle. It had to be a shape that cannot be said to be close to. This is because, for example, the ceramic paper slips on the corrugator, that is, the followability of the ceramic paper to the corrugator is low.

  In this respect, this paper is superior in followability to a corrugator compared to conventional ceramic paper. Therefore, this paper can have the cell 11 of the shape close | similar to a perfect circle compared with the conventional ceramic paper.

  The honeycomb structure 1 shown in FIGS. 1 and 2 can be formed by bonding the apex portions of the cells 11 of the corrugated paper 10 and the flat papers 20a and 20b with an adhesive. That is, for example, an adhesive is applied to the apex portion of each cell 11 of the corrugated paper 10, and then the apex portion of each cell 11 of the corrugated paper 10 and one flat paper 20a and the other flat paper 20b. The honeycomb structure 1 can be formed by press-contacting each.

  As a result, the honeycomb structure 1 can have a honeycomb shape in which voids 12 are formed between the cells 11 and the flat papers 20a and 20b. For example, as will be described later, the gap 12 can be used as a space for supporting a functional agent, and can also be used as a passage through which a fluid to be processed by the functional agent flows.

  Moreover, in the honeycomb structure 1, the thickness T1 of the corrugated paper 10 and the thickness T2 of the flat papers 20a and 20b are both 500 μm or less. Note that the corrugated paper 10 may cause the thickness T1 of the corrugated paper 10 to be slightly smaller than the thickness T2 of the flat papers 20a and 20b.

  On the other hand, the height H of the cells 11 of the corrugated paper 10 (in the honeycomb structure 1, the distance between the one flat paper 20a and the other flat paper 20b) is, for example, within a range of 0.5 to 50 mm. Preferably, it can be in the range of 0.7 to 30 mm, and more preferably in the range of 1.0 to 20 mm.

  Moreover, the width W of the cells 11 of the corrugated paper 10 (that is, the interval between the plurality of cells 11) can be, for example, in the range of 1 to 50 mm, and preferably in the range of 1.5 to 30 mm. More preferably, it can be in the range of 2.0 to 20 mm.

  Moreover, this structure can be a honeycomb structure including the corrugated paper 10 stacked in multiple stages. FIG. 3 is a perspective view of an example of a filter according to this embodiment (hereinafter referred to as “the present filter 3”) having such a honeycomb structure 2 as the present structure.

  As shown in FIG. 3, the filter 3 includes a honeycomb structure 2 including corrugated paper 10 and flat paper 20 that are alternately stacked, and a rectangular frame-shaped casing portion 30 that surrounds the outer periphery of the honeycomb structure 2. And have. For example, stainless steel (SUS) or the like can be used as the material constituting the casing 30. The honeycomb structure 2 can be formed, for example, by stacking a plurality of honeycomb structures 1 shown in FIGS. 1 and 2.

  The honeycomb structure 2 carries a functional agent (not shown). As this functional agent, according to the use of this filter 3, what has a suitable function can be selected suitably, and can be used.

  That is, as the functional agent, for example, from a gas phase such as air, a volatile organic compound (VOC), a basic gas such as ammonia, a sulfur oxide (SOx), a nitrogen oxide (NOx), A catalyst or adsorbent for removing acidic gas such as chlorine can be used. Specifically, for example, zeolite, metal oxide (such as titanium oxide), activated carbon, and silica gel can be used.

  Such a functional agent is supported on the honeycomb structure 2 by, for example, immersing the honeycomb structure 2 in a solution containing the functional agent for a predetermined time and then drying the honeycomb structure 2. be able to. That is, the functional agent is fixed to the surfaces of the corrugated paper 10 and the flat paper 20 constituting the honeycomb structure 2.

  The present filter 3 having the honeycomb structure 2 carrying such a functional agent can purify a gas such as air by the functional agent. That is, for example, in the filter 3, by passing a gas to be processed through a gap 12 (see FIG. 2) formed between the cell 11 of the corrugated paper 10 and the flat paper 20, It is possible to effectively remove harmful substances such as VOC contained in the.

  Specifically, for example, a harmful substance is contained in the direction indicated by the arrow A shown in FIG. 3 from the surface of one side of the honeycomb structure 2 of the filter 3 through the gap 12 of the honeycomb structure 2. Circulate gas. As a result, the concentration of harmful substances contained in the gas discharged from the surface on one side of the honeycomb structure 2 is effectively reduced as compared with the concentration in the gas before passing through the honeycomb structure 2. can do.

  The honeycomb structure 2 can be a fired honeycomb structure. That is, in this case, for example, first, the corrugated paper 10 and the flat paper 20 are laminated to form the honeycomb structure 2. Next, a functional agent is supported on the honeycomb structure 2. Then, the honeycomb structure 2 carrying the functional agent is fired.

  Firing can be performed, for example, by heating the honeycomb structure 2 at a temperature in the range of 300 to 800 ° C. for about 30 minutes to 24 hours. By this firing, organic components (organic fiber, organic binder, etc.) contained in the honeycomb structure 2 are substantially removed. Therefore, the fired honeycomb structure 2 is supported mainly by rock wool and glass fibers constituting the corrugated paper 10 and the flat paper 20.

  For this reason, when this structure is the fired honeycomb structure 2, in order for this structure to have sufficient strength, this paper (that is, corrugated paper 10 and flat paper 20) has an average fiber diameter. It is preferable to contain the glass fiber which exists in the suitable range as mentioned above.

  Moreover, in this case, it is more preferable that the present paper contains glass fibers whose average fiber diameter and average length are each in a suitable range as described above. Furthermore, in this case, it is particularly preferable that the present paper contains glass fibers whose average fiber diameter and average length are each in a suitable range as described above at a blending ratio within the preferable range as described above.

  As shown in FIG. 3, the present structure is not limited to a structure in which the corrugated paper 10 and the flat paper 20 are stacked on top of each other. For example, the honeycomb structure 1 as shown in FIGS. It can also be set as a roll-shaped structure formed by concentrically winding. Moreover, the honeycomb structure 2 can be subjected to a curing treatment by impregnating the honeycomb structure 2 before firing with an inorganic binder. In addition to the average fiber diameter and average length of the glass fiber, the thickness and the weight of the paper, the shot content of the rock wool contained in the paper, the rock wool in the inorganic fibers contained in the paper The preferred ranges described above for the sum of the content of glass and the content of glass fiber, etc., also apply to the present paper constituting the present structure before firing and after firing.

  Next, specific examples will be described.

[Example 1]
In Example 1, the relationship between the average fiber diameter and average fiber length of glass fibers and the strength of inorganic fiber paper (rock wool paper) containing the glass fibers and rock wool was examined.

  As the rock wool, rock wool manufactured using an electric furnace was used. The average fiber diameter of this rock wool was 2.2 μm. The rock wool had a shot content of 212 μm or more in diameter of 1.0% by weight or less, and a shot content of less than 212 μm in diameter had a content of 18.9% by weight or less.

  As the glass fiber, five types of chopped strands having different combinations of average fiber diameter and average fiber length were used. That is, a glass fiber having an average fiber diameter of 6 μm and an average fiber length of 3 mm, a glass fiber having an average fiber diameter of 6 μm and an average fiber length of 6 mm, an average fiber diameter of 6 μm and an average fiber Either a glass fiber having a length of 10 mm, a glass fiber having an average fiber diameter of 10 μm and an average fiber length of 6 mm, or a glass fiber having an average fiber diameter of 10 μm and an average fiber length of 13 mm Was used. Moreover, pulp, polyvinyl alcohol fiber, and PET fiber were used as the organic fiber.

  And the slurry which contains 75 weight part rock wool and 25 weight part glass fiber as an inorganic fiber, and also contains 30 weight part organic fiber was prepared. Next, by a wet papermaking method using a paper machine, five types of rock wool having a thickness of 200 μm from the slurry, containing rock wool as a main fiber, and further containing any of the above five types of glass fibers. Paper was manufactured. Furthermore, after impregnating silica sol in a part of each rock wool paper, it was baked by heating at 500 ° C. for 3 hours to produce 5 types of baked rock wool paper.

  And from each of the five types of rock wool paper that has not been fired and the five types of rock wool paper that have been fired, a test piece having a length of 100 to 200 mm and a width of 15 mm is prepared, and in accordance with JIS P8113, The tensile strength of the test piece was measured.

  In addition, as a comparative example, an inorganic fiber paper (ceramic paper) containing a ceramic fiber having a thickness of 200 μm and an average fiber diameter of 2.8 μm as a main fiber and no glass fiber by a similar wet papermaking method. ) Was manufactured. And similarly about this ceramic paper, the tensile strength before baking and after baking was measured.

  FIG. 4 shows an example of the result of measuring the tensile strength. In FIG. 4, the horizontal axis indicates a combination of the average fiber diameter and average fiber length of glass fibers contained in rock wool paper (however, “Comparative Example” indicates ceramic paper), and the vertical axis indicates each. The tensile strength (N / 15 mm) per 15 mm length of a test piece made of paper is shown. Moreover, in FIG. 4, the bar shown by white shows the result before baking, and the bar shown by black shows the result after baking.

  As shown in FIG. 4, the tensile strength of each non-fired rock wool paper showed no significant difference depending on the type of glass fiber contained, and was lower than the tensile strength of unfired ceramic paper. In contrast, the tensile strength of each fired rock wool paper was significantly higher than the tensile strength of the fired ceramic paper.

  Moreover, the tensile strength of the rock wool paper after baking containing the glass fiber whose average fiber diameter is 6 micrometers was higher than the tensile strength of the rock wool paper after baking containing the glass fiber whose average fiber diameter is 10 micrometers. In particular, the tensile strength of the fired rock wool paper containing glass fibers having an average fiber diameter of 6 μm and an average fiber length of 6 mm is such that the average fiber diameter is 6 μm and the fiber length is 3 mm or 10 mm. It was higher than the tensile strength of the rock wool paper after firing containing certain glass fibers.

  Thus, by including glass fibers having an average fiber diameter of 6 μm or 10 μm, the tensile strength of the fired rock wool paper could sufficiently exceed the tensile strength of the ceramic paper.

  Moreover, the tensile strength of the baked rock wool paper was able to be raised especially by containing 6 micrometers glass fiber whose average fiber diameter is less than 10 micrometers. Furthermore, rock wool paper containing glass fibers having an average fiber diameter of 6 μm and an average fiber length of 6 μm could have a particularly high tensile strength.

[Example 2]
In Example 2, the relationship between the blending ratio of rock wool and glass fiber and the characteristics of the inorganic fiber paper was examined.

  As the rock wool, the same one as used in Example 1 was used. As the glass fiber, a chopped strand having an average fiber diameter of 6 μm and an average fiber length of 6 mm was used. Moreover, pulp, polyvinyl alcohol fiber, and PET fiber were used as the organic fiber.

  And five types of inorganic fiber papers having different blending ratios were produced from the slurry containing rock wool and glass fibers as inorganic fibers in different blending ratios by the same wet papermaking method as in Example 1 above. .

  That is, inorganic fiber paper containing 100 parts by weight of rock wool and 0 (zero) parts by weight of glass fiber as inorganic fibers (that is, rock wool paper not containing glass fiber), and 75 parts by weight of rock as inorganic fibers. Inorganic fiber paper containing wool and 25 parts by weight glass fiber, inorganic fiber paper containing 50 parts by weight rock wool and 50 parts by weight glass fiber as inorganic fiber, 25 parts by weight rock wool as inorganic fiber, and Inorganic fiber paper containing 75 parts by weight of glass fiber, and inorganic fiber paper containing 0 (zero) parts by weight of rock wool and 100 parts by weight of glass fiber as inorganic fibers (that is, glass not containing rock wool) Fiber paper).

  Furthermore, each inorganic fiber paper is immersed in a solution containing silica sol as a functional agent, and then each inorganic fiber paper after the immersion is dried, thereby producing five types of inorganic fiber paper supporting the functional agent. did. Furthermore, a part of each inorganic fiber paper carrying a functional agent was fired under the same conditions as in Example 1 to produce five types of fired inorganic fiber paper.

  And tensile strength was measured similarly to said Example 1 about each of five types of inorganic fiber paper which was not baked, and five types of baked inorganic fiber paper. Moreover, the ceramic paper similar to said Example 1 was manufactured as a comparative example, and the tensile strength was measured.

FIG. 5 shows an example of the results of evaluating the tensile strength and other characteristics of each inorganic fiber paper and ceramic paper. In FIG. 5, for each inorganic fiber paper, the blending amounts (parts by weight) of rock wool and glass fiber are shown, and for the unfired inorganic fiber paper and ceramic paper, the average US basis weight (g / m ² ), thickness Inorganic (calcined) showing thickness (μm), average density (g / cm ³ ), tensile strength per 15 mm length (N / 15 mm), loss on ignition (%), and water retention (g / m ² ) For fiber paper and ceramic paper, the tensile strength per 15 mm length (N / 15 mm), the loading amount of functional agent (g / m ² ), and the average density (g / cm ³ ) are shown. In addition, as thickness, the arithmetic mean value of the value measured about ten test pieces is shown. Moreover, as tensile strength, the arithmetic mean value of the value measured about three test pieces is shown. The ignition loss was calculated as a percentage of the ratio of the weight (g) of the paper reduced by firing to the weight (g) of the paper before firing, by measuring the weight of the paper before and after firing by a method according to JIS P8128. . The water retention amount was calculated by dividing the difference in weight (g) between the test piece impregnated with water and the dried test piece by the area (m ² ) of the test piece.

  As shown in FIG. 5, the tensile strength of the unfired inorganic fiber paper was lower than that of the ceramic paper. On the other hand, the tensile strength of the baked inorganic fiber paper increased as the blending ratio of the glass fibers contained in the inorganic fiber paper increased.

  That is, the tensile strength of the fired inorganic fiber paper having a glass fiber blending ratio of 25 parts by weight is equal to the tensile strength of the ceramic paper, and the tensile strength of the fired inorganic fiber paper having a higher glass fiber blending ratio. The strength was higher than the tensile strength of the ceramic paper.

  In this way, the inorganic fiber paper containing rock wool as the main fiber contains glass fibers with an appropriate combination of average fiber diameter and average fiber length in an appropriate blending ratio, so that after firing, ceramics It was confirmed that it could have a tensile strength equal to or higher than that of paper.

  In addition, as the compounding ratio of the glass fibers increases, the heat resistance of the inorganic fiber paper decreases and the cost required for the production also increases. For this reason, it is considered that the blending ratio of rock wool and glass fiber is preferably in the range of 75 parts by weight to 25 parts by weight or the vicinity thereof in which the tensile strength after firing reaches the tensile strength of the ceramic paper. It was.

[Example 3]
In Example 3, the relationship between the kind of inorganic fiber used as the main fiber and the characteristics of the inorganic fiber paper was examined. As the main fiber, either rock wool, ceramic fiber or biosoluble fiber was used.

  As the rock wool, the same one as used in Example 1 was used. This rock wool had an average fiber diameter of 3 μm, the content of shots having a diameter of 212 μm or more was substantially zero wt%, and the content of shots having a diameter of less than 212 μm was 15 wt%.

  As the ceramic fiber, an alumina silica fiber (Fineflex, Nichias Corporation) was used. This ceramic fiber had an average fiber diameter of 3 μm, a content of shots having a diameter of 212 μm or more was 10% by weight, and a content of shots having a diameter of less than 212 μm was 30% by weight.

  As the biosoluble fiber, silica-magnesia-calcia fiber (Fineflex-E, NICHIAS Corporation) was used. This biosoluble fiber had an average fiber diameter of 3 μm, a content ratio of shots having a diameter of 212 μm or more was 10% by weight, and a content ratio of shots having a diameter of less than 212 μm was 30% by weight.

  As the glass fiber, a chopped strand having an average fiber diameter of 6 μm and an average fiber length of 6 mm was used. Moreover, pulp, polyvinyl alcohol fiber, and PET fiber were used as the organic fiber.

  And as a 1st inorganic fiber paper, from the slurry containing 75 weight part rock wool, 25 weight part glass fiber, and 15 weight part organic fiber, the wet papermaking similar to said Example 1 is carried out. By the method, inorganic fiber paper (rock wool paper) containing rock wool as the main fiber was produced.

  Further, as the second inorganic fiber paper, a wet papermaking similar to that in Example 1 above is made from a slurry containing 75 parts by weight of ceramic fibers, 25 parts by weight of glass fibers, and 15 parts by weight of organic fibers. By the method, inorganic fiber paper (ceramic paper) containing ceramic fibers as main fibers was produced.

  Further, as the third inorganic fiber paper, from the slurry containing 75 parts by weight of the biosoluble fiber, 25 parts by weight of the glass fiber, and 15 parts by weight of the organic fiber, the same as in Example 1 above. An inorganic fiber paper (biosoluble paper) containing biosoluble fibers as main fibers was produced by a wet papermaking method.

  And about each of these rock wool paper, ceramics paper, and biosoluble paper, corrugated workability and the presence or absence of the formation of the hole by dropping of a shot were evaluated.

  In evaluating corrugating workability, each paper was first corrugated using a pair of gear-like corrugators rotating while meshing with each other.

  Then, each corrugated paper is visually observed and no breakage occurs, and if it has a corrugated corrugated shape, it is judged that the workability is good, and the breakage occurs or the corrugation When the shape was not given, it was judged that the workability was poor.

  The presence or absence of hole formation due to shot drop was observed with each microscope corrugated paper using a microscope, and when a hole with a diameter of 200 μm or more was present, it was determined that the hole was formed due to shot drop and the diameter was 200 μm. When the above holes did not exist, it was judged that no holes were formed due to shot dropping.

  FIG. 6 shows an example of the results of evaluating the corrugation processability and the presence or absence of holes due to shot dropping for each paper. As shown in FIG. 6, the corrugated workability of rock wool paper containing rock wool as a main fiber that does not substantially contain a shot having a diameter of 212 μm or more and that has a low content of shots having a diameter of less than 212 μm. Excellent evaluation results were obtained that were good and that no holes were formed due to shot dropping.

  On the other hand, for the ceramic paper having a relatively large shot diameter and a relatively large shot content, it was evaluated that the corrugated workability was good, but the formation of holes due to shot dropping occurred.

  In addition, it was evaluated that the biosoluble paper having a relatively large shot diameter and a relatively high shot content had poor corrugation workability and had holes formed due to shot dropping.

  Thus, the rock wool paper containing the rock wool manufactured using the electric furnace as a main fiber had characteristics more suitable for corrugating than ceramic paper and biosoluble paper.

1 is a perspective view of an example of a honeycomb structure according to an embodiment of the present invention. It is sectional drawing about an example of the honeycomb structure which concerns on one Embodiment of this invention. It is a perspective view about an example of a filter concerning one embodiment of the present invention. It is explanatory drawing which shows an example of the result of having measured the tensile strength of the inorganic fiber paper which concerns on one Embodiment of this invention. It is explanatory drawing which shows an example of the result of having evaluated the characteristic of the inorganic fiber paper which concerns on one Embodiment of this invention. It is explanatory drawing which shows an example of the result of having evaluated the corrugate workability of the inorganic fiber paper which concerns on one Embodiment of this invention.

Explanation of symbols

  1, 2 honeycomb structure, 3 filter, 10 corrugated inorganic fiber paper (corrugated paper), 11 cells, 12 voids, 20 flat inorganic fiber paper (flat paper), 30 housing part.

Claims (6)

The thickness is 500 μm or less,
Contains rock wool as the main fiber,
Further containing glass fiber ,
Fired inorganic fiber paper,
The glass fiber has an average fiber diameter in the range of 3 to 10 μm and an average fiber length in the range of 3 to 15 mm,
The inorganic fiber constituting the inorganic fiber paper contains the rock wool in the range of 65 to 85% by weight and the glass fiber in the range of 15 to 35% by weight. paper. Inorganic fiber paper of claim 1 that a basis weight is characterized in that it is in the range of 5 to 500 g / m ^2. The rock wool is not more than 2% by weight content of more shots diameter 212 m, and shot content of a diameter less than 212 m are described in claim 1 or 2, characterized in that 20 wt% or less Inorganic fiber paper. A honeycomb structure comprising the inorganic fiber paper according to any one of claims 1 to 3 which has been corrugated. The honeycomb structure according to claim 4 , wherein a catalyst or an adsorbent is supported. A filter comprising the honeycomb structure according to claim 4 or 5 .

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