JP2000070631A - Manufacture of carbon fiber filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a carbon fiber filter to have flammability and high performance at a low cost without generating a hazardous material in incineration by a method wherein a carbon fiber and a thermofusible non-halogen based chemical fiber are mixed to form a sheet shape, the sheet shaped product is heated at a melting point of the fiber or higher up to and including an oxidizing loss start temperature of the carbon fiber with a thermally continuous pressing furnace or the like, and mutual bond of fibers is executed to adjust a thickness. SOLUTION: A carbon fiber precursor is prepared by applying an unmeltable treatment to a spun fiber prepared by discharging from a spinning nozzle after thermally fusing an isotropic pitch wherein condensed multi-ring hydrocarbon is polymerized, and the precursor is treated by carbonization in an inert gas to prepare a curved carbon fiber 1. The fiber 1 together with a thermofusible core-sheath typed polyester fiber piece 2 are previously fibrillated, mixed by compressed air 4, transferred to a card machine 7 with a travelling belt 6 to form a sheet shape 8, and the sheet shaped product is rolled to a temporary carbon fiber filter 12 with a temporary hot roll 10. Then, the temporary filter 12 is heated while it is pressed to a specific thickness with hot rolls 13, 14 to prepare a required carbon filter 15. Thereby, the filter 15 which has high performance at a low cost and does not generate hazardous material and halogen even in incineration, can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a carbon fiber filter, and more particularly to a carbon fiber filter for a range hood using a specific carbon fiber as a material and a heat-fusible chemical fiber as a bonding material. And a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, in each home, a filter device has been widely used at an upper part of a gas-con stove for cooking, mainly for removing oil content in heat exhaust. And as a filter body for this filter device, heat resistance and fire resistance are required, while glass fiber and metal fiber are manufactured, priced,
Since there are many problems in disposal and the like, chemical fibers that have been subjected to a flame-retardant treatment or the like have been frequently used.

[0003] However, despite the fact that it is flame-retardant, it is a chemical fiber, so if it ignites with oil or the like adsorbed in the unlikely event that it is adsorbed, the flame will not spread, but the heat will not spread. And may fall off of the mounting frame and fall down, which is less than perfect from a safety standpoint for those who are near the worktop below.

[0004] In particular, as is the case with Chinese and French dishes, ignition of alcohol in a pot or a frying pan or a large amount of high-temperature oil droplets jump up. Even in such a case, ignition of a sheet or heat shrinkage occurs. There must be no. Also, in these cases or in case of any accident, the flame should suddenly rise and the sheet should not break even when dynamic pressure is applied. However, it is very difficult with ordinary chemical fiber, so halogen-based flame retardant Is often used. However, this may lead to the generation of dioxin when the used filter is incinerated at a waste disposal plant, and is not preferable in terms of environmental pollution.

[0005] For this reason, not only is it fire-resistant and heat-resistant, but it does not shrink thermally even in the event of ignition of oil, etc., and there is no problem in terms of disposal. There is no danger for those who are near the heat source,
Naturally, it has been desired to realize a filter (device) that is excellent in terms of the original performance of the filter such as air resistance and dust removal. As such a filter, a carbon fiber filter is currently attracting attention.

[0006]

However, when producing a filter using carbon fibers, there is a problem how to produce a desired carbon fiber filter.

That is, since carbon fibers have no adhesive force, it is necessary to bond, bond, or bond the carbon fibers with each other by some means in order to manufacture a sheet. The wet method (papermaking method) using only a liquid binder has the following problems.

(1) Since the resin is cured in a state where the thickness is suppressed by the surface tension of water, the density is high and the resin is not suitable for a filter. Further, since the thickness of the sheet is determined by the fibers and binder used, it is difficult to obtain an optimum filter.

(2) Phenolic resin binders and phosphoric acid-based flame retardants having high flame retardancy are difficult to use because the water quality of waste liquid is strictly regulated. In addition, under the recent strict requirements for environmental pollution prevention, liquid binders and flame retardants (for example, vinyl chloride and bromine based) that generate harmful substances such as dioxin when the used filter is finally disposed of by incineration. Can not be used.

[0010] In the case of manufacturing by a wet method using only fused fibers for bonding, there are the following problems. (1) Since curing is promoted in a state where water is evaporated, there is no effect of surface tension of water, and therefore, the density can be reduced as compared with a case where only a liquid binder is used. However, if the carbon fibers are not curved, the density cannot be reduced to a density suitable for a filter.

(2) Carbon fibers available as curved fibers include:
At present, there is only general-purpose carbon fiber (Donacarb),
This is because the strength of the fiber is not so strong, and the fiber is cut short by stirring in the mixing tank.

(3) When the fused fibers are used by a wet method, they tend to be pills, so that only fibers having a fiber length of about 10 mm can be used even if they are 5 mm long. For this reason, both the carbon fiber and the fused fiber are short in fiber, and there are many fiber drops from the sheet, which is not preferable as a household range hood filter.

[0013] Further, in the case of manufacturing by a wet method using a liquid binder and fused fibers for bonding, there are the following problems. (1) While the liquid binder has a small effect of preventing fiber dropping, the flame retardancy is insufficient and waste liquid treatment becomes a problem.

In addition to the above, it is necessary to satisfy various requirements as a filter, particularly as a filter for a range hood. Therefore, it has been desired to develop a method for producing a carbon fiber filter which does not cause such a problem and which is inexpensive and has high performance.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has been made in consideration of a method in which a mixed fiber of a specific carbon fiber and a specific heat-fusible material fiber is formed into a sheet by a non-wet method. It will be manufactured while joining and adjusting the thickness under heating. Specifically, it is performed as follows.

According to the first aspect of the present invention, there is provided a sheet producing step in which a mixture of carbon fibers and heat-fusible non-halogen chemical fibers is formed into a sheet by a non-wet sheet producing machine. The prepared sheet is
Heat-fusible non-halogen chemical fiber (Halogen such as chlorine and bromine is not used as a raw material such as CFC, but also as a modifier (material) by a hot continuous press furnace and / or hot roll press. (Not included) and heating below the melting temperature of carbon fibers and below the temperature at which oxidation of the carbon fibers begins, thereby bonding the fibers to each other. In addition, press gaps or direct pressing of a hot continuous press furnace and / or hot roll press machine are performed. Adjusting the thickness by pressure.

The following operation is performed by the above configuration. In the sheet making step, for example, a cotton-like fibrous material in which carbon fibers and heat-fusible non-halogen chemical fibers are mixed by a non-wet sheet manufacturing machine such as using a card method (card machine) in which unevenness is unlikely to occur. In other words, a cloth-like sheet (in principle, a sheet in a so-called web state in which fibers are joined by frictional resistance, and not in a state of being strongly joined and adhered as at the time of completion) is produced.

In this case, since the so-called dry method is used, breakage of the carbon fiber is small, and the thickness and density of the sheet can be easily controlled. If needling is performed after this sheet preparation step, the fibers are entangled in the thickness direction of the sheet, and the tensile strength of the sheet can be improved.

In the joining thickness control step, the mixture or its (air) atmosphere is oxidized by a hot continuous press furnace and / or a hot roll press machine to a temperature higher than the melting point of the heat-fusible non-halogen chemical fiber. At a temperature equal to or lower than the weight-starting temperature, the carbon fiber and the heat-fusible non-halogen chemical fiber are joined (the fibers are strongly bonded), and the thickness of the sheet is optimally adjusted as a filter.

In the invention described in claim 2, the sheet making step is a predetermined basis weight making step for forming a sheet having a basis weight of 20 to 50 g / m ² , and the joining thickness controlling step is such that the thickness is 5 g. / Cm ² under a load of 0.
This is characterized in that it is a step of producing a predetermined thickness of 6 to 1.8 mm.

With the above configuration, the following operations are performed.
In a predetermined basis weight producing step as a sheet producing step, a slightly thicker sheet having a basis weight of 20 to 50 g / m ² is produced. Next, in the predetermined thickness forming step of the joining thickness control step, the thickness of the carbon fiber sheet is set to 5 g / cm.
Bonding by heat fusion of fibers by heating with a hot roll, atmosphere, hot press, etc. while adjusting the roll spacing etc. so as to have a thickness of 0.6 to 1.8 mm under the load (pressing) of ² I do.

The invention according to claim 3 has a core / sheath type selecting step of selecting a core / sheath type as the heat-fusible non-halogen chemical fiber to be processed before the sheet making step. The bonding and thickness control step is characterized in that the temperature is set to be equal to or lower than the melting point of the core of the core-sheath type heat-fusible chemical fiber and equal to or higher than the melting point of the sheath.

With the above configuration, the following operation is performed.
In the core-sheath type selection step, as the heat-fusible non-halogen chemical fiber of the raw material of the sheet produced in the sheet production step, the center has a relatively high melting point (about 200 to 255 ° C., depending on the manufacturer and product). ) A core-sheath type in which a sheath made of a different material made of a material having a relatively low melting point (about 100 to 110 ° C.) is applied to a core made of a material is selected.

In the joining thickness control step, the temperature of the carbon fiber and the heat-fusible chemical fiber is lower than the melting point of the core (about 255 ° C.) and naturally lower than the oxidation loss point of the carbon fiber, and the melting point of the sheath (about 11
0 ° C.) (usually 220 ° C. or less, preferably 130 ° C. to 180 ° C.), so that the properties of the heat-fusible non-halogen chemical fiber as a fiber are not lost and, of course, there is no oxidative loss of carbon fiber. The mixed fiber is bonded and bonded.

In the invention according to claim 4, prior to the sheet forming step, the heat-fusible non-halogen chemical fiber to be processed has a fiber length of 75 mm or less.
It is characterized by having a heat-fusing non-halogen-based chemical fiber length selection step of selecting a length of not less than mm.

With the above configuration, the following operation is performed.
In the heat-fusing non-halogen chemical fiber selection step, as the heat-fusing non-halogen chemical fiber mixed with carbon fiber,
75m or less 35m from the viewpoint of mixing properties and prevention of fiber dropping
m or more, preferably 51 mm ± 5 mm in length. As a result, both the carbon fibers and the heat-fusible non-halogen-based chemical fibers have a sufficient length, so that the fiber drops from the sheet are reduced.

In the invention according to the fifth aspect, prior to the sheet forming step, there is provided a polyester selection step for selecting PET, particularly polyester fiber, as a heat-fusible non-halogen chemical fiber to be treated. It is characterized by doing.

With the above configuration, the following operation is performed.
In the polyester selection step prior to the sheet production step, as heat-fusible non-halogen chemical fibers to be mixed with carbon fibers as a bonding material, heat-fusible polyester fibers (including mixtures of up to 15%, so-called polyester fibers) ) Is selected, and the chemical resistance and water resistance are also excellent.

In the invention described in claim 6, prior to the sheet forming step, there is provided an optimum carbon fiber diameter selecting step of selecting carbon fibers having an outer diameter of 19 microns or more and 12 microns or more as the carbon fibers to be processed. It is characterized by doing.

With the above configuration, the following operation is performed.
In the optimal carbon fiber diameter selection step prior to the sheet making step, the outer diameter is 19 microns or less, 12 microns or more, preferably 18 microns or less, 12.5 microns or more, and more preferably 13 microns (including an error of several percent on average). In addition, the carbon fiber filter has a moderate strength because of the existence of some variation.) On the other hand, unlike the glass fiber etc. (because it has other properties), the carbon fiber filter pierces human skin. No discomfort, so-called tingling, occurs.

The invention according to claim 7 has an optimum resistance value selecting step of selecting a carbon fiber having a volume resistivity of 100 to 1000 Ω · cm as a carbon fiber to be treated prior to the sheet forming step. It is characterized by having.

With the above configuration, the following operation is performed.
In the optimum resistance value selection step prior to the sheet production step, a carbon fiber having a relatively large volume specific resistance value of 100 to 1000 Ω · cm is selected, so that a short circuit, a spark or the like hardly occurs. Combustible dust in the exhaust,
Even if there are oil droplets, it is difficult to ignite or catch fire.

Further, carbon fibers having a volume resistivity value within this range have a relatively low carbonization (treatment) temperature and, as a result, a low elastic modulus. For this reason, even though the fiber diameter is relatively large, discomfort caused by the fiber piercing the human skin,
No so-called tingling occurs. Furthermore, even if the fibers are cut apart and adhere to the exhaust duct, they do not lead to galvanized corrosion of the relevant portion.

The invention according to claim 8 is characterized in that prior to the sheet producing step, there is provided a step of selecting a curved carbon fiber as a carbon fiber to be processed.

Here, the term "curved carbon fiber" means a fiber having an aspect ratio (length / diameter) of 50 or more and a specific volume larger than that of a straight carbon fiber. Specifically, when the aspect ratio is 500, the specific volume is 9 cm ³ /
g is a carbon fiber having a bendability of at least g and an aspect ratio of 50 or more. In this case, the numerical range is set as follows: those having a specific volume of less than 9 cm ³ / g at an aspect ratio of 500 are inferior in curvature, and those having an aspect ratio of less than 50 exhibit a small degree of curvature. It depends.

The specific volume of a normal straight carbon fiber at an aspect ratio of 500 is 7 to 8 cm ³ / g. In addition, the specific volume mentioned here is measured under a load (suppression) of 150 g / cm ² with a sample placed so as to fill the volume of a 500 ml beaker.

With the above configuration, the following operation is performed.
Since the carbon fibers of the sheet material are curved, not only the entanglement of the fibers increases, but also the sheet becomes three-dimensional despite the thin sheet shape, and the strength is greatly improved. (In the case of straight carbon fibers, it is difficult to hold the web because the frictional resistance and entanglement between the fibers are small.) In addition, since the bulk density is large, the surface area increases, and dust, particularly oil droplets, is reduced. Adsorption performance is excellent.

According to the ninth aspect of the present invention, in the carbon fiber ratio adjusting step prior to the sheet forming step, the carbon fiber as a mixture to be treated is not more than 85% by weight.
5% by weight or more (therefore, the heat-fusible non-halogen chemical fiber is generally 45% by weight or less and 15% by weight or more.
When a small amount of a reinforcing material, a performance improver, or the like is contained, the amount is further reduced accordingly. ), And preferably not more than 80% by weight and not less than 60% by weight, more preferably not less than 65% by weight and not more than 70% by weight.

With the above configuration, the following operation is performed.
55 carbon fibers formed by strongly bonding each carbon atom to each other
Since the weight percentage is not less than the weight percent, even if the attached oil droplets are ignited due to sparks or the like flying from a lower cooking table or the like, the fire does not spread. That is, self-extinguishing properties are exhibited. Moreover, since the carbon fiber is 85% by weight or less, that is, an appropriate amount of the heat-fusible non-halogen chemical fiber is present, the bonding and adhesion between the fibers are excellent. Furthermore, as the amount of carbon fiber becomes 65 to 70% by weight, not only both of these properties become sufficient, but also less expensive carbon fiber as compared with the heat-fusible non-halogen-based chemical fiber, the cost is lower. Also.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on its embodiments. First Embodiment First, a known method (for example, Japanese Patent Publication No. 58-057374, Reinforced Plastics, Vol. 34, No. 3, page 89, "Characteristics of Curved Pitch-Based Carbon Fiber", etc.)
A curved carbon fiber is manufactured by the vortex method (RGJ method).

Specifically, first, an isotropic pitch obtained by polymerizing a condensed polycyclic hydrocarbon is prepared. Next, the pitch is heated and melted and discharged from the spinning nozzle. At the same time, the heated air is totally discharged from six places around the spinning nozzle in the same direction as the discharge direction (however, in a tornado shape in the case of six air flows, in a discharge direction). Spiral is spouted in a two-dimensional plane orthogonal to the spun fiber) to produce spun fibers.

Here, the heated air serves to prevent the discharged material from being cooled immediately, and to obtain fibers having an appropriate length and diameter, and consequently a curved shape. The above spun fibers are collected by, for example, a net, and subjected to infusibilization treatment (oxidation treatment).
Is applied. Thereby, a carbon fiber precursor can be produced. 700 ° C. to 800 ° C. in an inert gas
At a temperature of 5 ° C. to form curved carbon fibers.

Here, the treatment temperature is set so that the volume resistivity of the carbon fiber is 100 to 1000 Ω · cm. The approximate relationship between the carbonization (processing) temperature and the volume resistivity is shown in FIG.
It changes depending on the processing time, fiber temperature and the like. FIG. 2 also shows an approximate relationship between the carbonization temperature and the bending stiffness (elastic modulus) (this is also only a guide).

However, controlling the carbonization temperature to a desired value such as the electrical resistance of the carbon fiber is disclosed in, for example, PCT / JP97 / 00588, "Sound Absorbing Insulating Material and Method for Producing the Same". Since it is a known technique and can be easily obtained by experiments on a case-by-case basis, further description is omitted.

At this time, the processing temperature in the subsequent step is usually 2
Since the use temperature of the product is relatively low at 20 ° C or lower (preferably 130 to 180 ° C) and usually 100 ° C or lower, the substance contained in the carbon fiber does not volatilize even if the carbonization temperature is low. In addition, since the carbonization temperature is low, the equipment is relatively simple and the cost is advantageous.

Next, FIG. 3 conceptually shows how the carbon fiber filter according to the present invention is manufactured using the carbon fiber. In the figure, reference numeral 1 denotes a curved carbon fiber (piece). 2 is a heat-fusible core-sheath type polyester resin fiber piece cut to a length of 51 cm. 3 is a nozzle. 4 is compressed air discharged from the nozzle. 5
Is a mixed deposit of curved carbon fibers and heat-fusible polyester resin fiber pieces. Reference numeral 6 denotes a transport belt. 7 is
It is a card machine. Reference numeral 8 denotes a mixture of a sheet-like curved carbon fiber and a heat-fusible polyester resin fiber piece. 9 is a conveyance belt. 10 is a temporary hot roll. 11 is a hot floor. Reference numeral 12 denotes a temporary carbon fiber filter. 13 and 14 are hot rolls. 15 is a carbon fiber filter.

Hereinafter, a method for manufacturing the carbon fiber filter itself will be described with reference to FIG. The heat-fusible core-sheath type polyester resin fiber was purchased from a manufacturer in the form of a fiber bundle, and cut into a length of 51 mm. At this time, the color was white. This is because it does not contain pigment, it is cheaper than black etc., and when mixed with carbon fiber, the blackness is somewhat weakened. This is to make it easy to do even a little.

Both the curved carbon fiber and the heat-fusible core-sheath type polyester fiber piece are opened with compressed air in advance.
This is dropped by a predetermined amount from above. At this time, compressed air is blown from a nozzle on the way to mix the two. Here, mixing with air is for reducing breakage due to collision of carbon fibers.

The mixture of the two fiber pieces falls onto a conveyor belt provided at the lower part of the room.
Connected to card machine. For this purpose, the mixture of the two fiber pieces is carried into a carding machine, where it is formed into a sheet having a predetermined basis weight in which the fibers are randomly arranged two-dimensionally, but naturally larger than the original.

Next, the sheet-like mixed fiber is transported to a temporary hot roll by a transport belt connected downstream of the card machine. At this time, the temporary hot roll and the opposing hot floor are maintained at about 160 ° C. by electric heating. By the way, at this time, the atmosphere from the downstream side of the card machine to the temporary hot roll has a temperature atmosphere of about 100 ° C. Under this condition, the sheet-like mixed fiber in contact with the temporary hot roll at about 160 ° C. may be heated to about 100 ° C. in advance, and immediately about 160 ° C., that is, the sheath of the heat-fusible polyester resin. The temperature is about 40 ° C. higher than the melting point.

For this reason, the sheath portion of the core-sheath type heat-fused polyester fiber (piece) immediately melts, and the carbon fibers and the carbon fiber and the heat-fused polyester fiber, and further, the heat-fused polyester fibers, especially the core. The parts are joined and adhered to each other to form a sheet-like temporary carbon fiber filter that withstands a certain amount of tensile force.

Since the temperature is below 100 ° C. up to the temporary hot roll, the sheet-like mixed fiber is easily separated from the conveyor belt and peeled off, while being transported onto the hot floor by the rotation of the temporary hot roll again and without difficulty. You. Next, under this condition, heating is performed while being pressed by an original hot roll so as to have a predetermined thickness, and a desired carbon fiber filter is obtained on the downstream side.

As shown in FIG. 4, the core-sheath type heat-fused polyester fiber used in the present embodiment has a core 41 made of a polyester resin fiber having a relatively high melting point of about 255.degree. Is a double-type fiber surrounded by a sheath 42 of a polyester resin having a relatively low melting point of about 110 ° C., and is widely marketed. In addition, the material having such a thermal melting point characteristic is excellent in heat resistance due to the high melting point of the core and the sheath, and the temperature control at the time of thermal fusion is easy.

Next, the fire resistance, heat resistance, and flame retardancy of this sheet-like carbon fiber filter were examined.
When exposed to the fire of the match, the heat-fused polyester resin in that portion burned, but the carbon fibers did not burn, and the shape of the bonded carbon fibers remained unchanged. Although the detailed mechanism is unknown, it is considered to be due to the adhesion of the carbon fiber itself due to the unburned residue of the resin fiber and the burning residue of the resin fiber in the portion and the heat generation.

As a second test, assuming that alcohol in a pot or a frying pan was burned, a large amount of oil droplets flew up, and furthermore, a flame started up due to sudden ignition, etc. Although exposed to such high heat and flame, sufficient heat resistance and the like were exhibited. Of course, no deformation or shrinkage of the sheet was caused by heat in any of the experiments.

Also, in the test of the filter property, there was no inferiority to the conventional synthetic fiber filter subjected to the flame retardant treatment. This is probably due to the excellent adsorption of carbon, especially for non-polar substances. In addition, it is considered that the heat-fusible resin is also originally a chemical fiber and has excellent adsorbability to oil droplets and the like. Furthermore, naturally, no undesirable phenomena such as water absorption were found.

(Second Embodiment) FIG. 5 conceptually shows another method and apparatus for manufacturing a carbon fiber filter according to the present invention. In this figure, reference numeral 50 denotes a pre-spreader for carbon fibers. Reference numeral 51 denotes a pre-spreader for heat-fusible polyester fibers. 52 is an opening mixer. 53 is a weighing machine. 54 is a card machine. 55 is a needling machine. Reference numeral 56 denotes a hot continuous hot press furnace. 57 is a hot press roll.

Hereinafter, the present embodiment will be described. First, the raw materials are the same as in the first embodiment. Less than,
The description will focus on a method for manufacturing a predetermined sheet. The carbon fibers are supplied to the carbon fiber preliminary opening machine in a mat form and are opened. As for the heat-fusible polyester fiber, a bundle cut to a predetermined length is supplied to the heat-fusible polyester fiber pre-spreader and spread.

A predetermined amount of each of the opened fibers is supplied to an opening mixer, and the fibers are opened and mixed a few times, particularly mixed.
The opened and mixed fibers are sent to a carding machine by a predetermined amount by a measuring machine. Opened and mixed fibers sent from the weighing machine by a fixed amount are arranged and arranged in a card machine, and the web (thin cloth determined from the basis weight) is prepared.
It is said.

Next, in order to adjust the thickness of the layer, prevent the fiber from dropping, and improve the strength, the needle is needled by a needling machine so that the upper fiber is entangled with the lower fiber by a needle. At this time, since the fiber is a curved fiber, the fiber is not broken by an excessive tensile force when pressed down by a needle. Furthermore, heat fusion is performed with a certain thickness while keeping the sheet having a large area in a hot continuous hot press furnace.

Finally, the sheet passes through a hot press roll consisting of two rotating hot rolls, and the thickness is precisely adjusted in the gap between the upper and lower hot rolls. Wearing is done.

Next, the carbon fiber filter manufactured in this embodiment was subjected to various tests in the same manner as in the first embodiment, but showed excellent properties.

It is needless to say that various modifications can be made in the present embodiment. For example, the needling machine shown in FIG. 5 is preferable, but is not always necessary depending on the length, diameter, and type of the fiber. Also, in the case of the convenience (restriction) of the equipment used by the manufacturer, or in the case of having expensive but highly accurate control means, as shown by the broken line in FIG. The heat-sealing of the carbon fiber and the heat-fusible polyester fiber and the adjustment of the sheet thickness may be performed using only one of a furnace and a hot press roll.

Although the present invention has been described based on the embodiments, it goes without saying that the present invention is not limited to these embodiments. That is, for example, the following may be performed. (1) Other carbon fibers such as mesophased and PAN are used. (2) Carbon fiber having a relatively large diameter is used, and is exposed to high-temperature steam to partially carbonize the carbon fiber to increase its surface area. To prevent tingling.

(3) The carbon fiber as the main raw material is a general-purpose pitch fiber, but includes a high-strength material such as mesophased and PAN in order to further improve the strength in case of sudden ignition below. Not. (4) A non-halogen (particularly chlorine or bromine) flame retardant (agent) is contained. (5) Activated carbon and various chemical substances are contained to achieve deodorization and the like. (6) Used for other purposes such as a filter for ventilation.

(7) It is used for business purposes and the like, and the discharge (exhaust) pressure of the exhaust fan may be large. (8) If a simple method for removing oil and the like attached to the filter is developed in the future, the filter is manufactured using a small amount of metal mesh or the like so that it can be reused.

(9) A sheet produced by spraying a thermosetting resin on a cotton-like or sheet-like carbon fiber and curing by heating is used in combination, or a method of spraying a thermosetting resin on the production of a sheet and heating and curing is used in combination. ing. (10) As a manufacturing step of the sheet before fiber bonding, other methods such as an air layer method are adopted instead of the card method.

(11) A substance other than polyester is used as the heat-fusible non-halogen chemical fiber. Alternatively, the color is set to the same black as that of the carbon fiber so that unevenness in the basis weight of the sheet is not noticeable. (12) Cutting of the heat-fused polyester fiber into a predetermined length
This is done by the material manufacturer. (13) With the development of future technology, some other means is adopted as a method for producing curved carbon fibers.

[0069]

As described above, according to the present invention, an inexpensive and high-performance carbon fiber filter can be easily manufactured by simple means and equipment. Further, since the wet method or the spraying of the thermosetting resin is not adopted, the range of choice of the joining resin is widened, and as a result, the product is excellent.

Further, there is no generation of harmful substances such as dioxin and halogens which may cause ozone layer destruction even during incineration as final disposal. Also, waste disposal at the time of manufacturing is easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an approximate tendency (relationship) between a carbonization temperature and a volume resistivity value.

FIG. 2 is a diagram showing approximate trends in carbonization temperature and elastic modulus.

FIG. 3 is a diagram conceptually showing a state of manufacturing and a manufacturing apparatus according to the first embodiment of the present invention.

FIG. 4 is a view conceptually showing the structure of a core-sheath type heat-fused polyester fiber.

FIG. 5 is a diagram conceptually showing a manufacturing state and a manufacturing apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Curved carbon fiber piece 2 Heat-fusible core-sheath type polyester resin fiber piece 3 Nozzle 4 Compressed air 5 Mixed deposit of both fiber pieces 6 Conveyor belt 7 Card machine 8 Mixed deposit of both fiber pieces 9) Conveyor belt 10 Temporary hot roll 11 Hot floor 12 Temporary carbon fiber filter 13 Hot roll (upper roll) 14 Hot roll (lower roll) 15 Carbon fiber filter 41 Core 42 Sheath 50 Pre-spreader for carbon fiber 51 Heat fusion Preliminary opening machine for conductive polyester fiber 52 Spreading mixer 53 Weighing machine 54 Card machine 55 Needling machine 56 Hot continuous hot press furnace 56 Hot press roll

Continued on the front page F term (reference) 4D019 AA01 AA02 BA03 BA13 BA17 BB03 BB08 BC10 BC11 BC15 BC20 BD01 CB06 DA03 DA06 4L047 AA03 AB02 AB07 AB09 AB10 BA03 BA09 BB06 BB09 BD01 CA19 CB05 CC12 DA00

Claims (9)

[Claims] 1. A sheet forming step in which a mixture of carbon fibers and heat-fused non-halogen chemical fibers is formed into a sheet by a non-wet sheet manufacturing machine; The fibers are joined to each other by heating to a temperature not lower than the melting point of the heat-fusible non-halogen chemical fiber and not higher than the temperature at which the carbon fiber starts to lose weight by a furnace and / or a hot roll press machine. And / or a joining thickness adjusting step of adjusting the thickness by a press gap of a hot roll press machine. 2. A method according to claim 1, wherein said sheet producing step has a basis weight of 20 to
A step of forming a predetermined basis weight for forming a sheet of 50 g / m ² , wherein the step of adjusting the thickness of the joint is a step of forming a predetermined thickness with a thickness of 0.6 to 1.8 mm under a load of 5 g / cm ^2. The method for producing a carbon fiber filter according to claim 1, wherein: 3. The heat-fusible non-halogen chemical fiber to be treated prior to the sheet producing step,
A core-sheath type selecting step of selecting a core-sheath type, wherein the bonding and thickness-adjusting step is performed by setting the temperature to a value equal to or lower than the melting point of the core of the heat-fusible non-halogen chemical fiber of the core-sheath type and equal to or higher than the melting point of the sheath. The method for producing a carbon fiber filter according to claim 1 or 2, wherein 4. Prior to the step of producing a sheet, the heat-fusible non-halogen chemical fiber to be treated is
4. The carbon fiber filter according to claim 1, further comprising a heat-fusing non-halogen chemical fiber length selecting step of selecting a fiber length of 75 mm or less and 35 mm or more. Manufacturing method. 5. The heat-fusible non-halogen chemical fiber to be processed is prepared prior to the sheet forming step.
5. The method for producing a carbon fiber filter according to claim 1, further comprising a polyester selection step of selecting polyester fibers. 6. An optimum carbon fiber diameter selecting step for selecting a carbon fiber having an outer diameter of not more than 19 microns and not less than 12 microns as a carbon fiber to be treated prior to the sheet producing step. The method for producing a carbon fiber filter according to any one of claims 1, 2, 3, 4, and 5. 7. Prior to the step of producing a sheet, the carbon fiber to be treated has a volume resistivity value of 100.
7. The method according to claim 1, further comprising the step of selecting an optimum resistance value for selecting a carbon material having a resistance of up to 1000 Ω · cm. Manufacturing method of fiber filter. 8. The method according to claim 1, further comprising a step of selecting a curved carbon fiber to select a carbon fiber containing the curved carbon fiber as a carbon fiber to be processed prior to the sheet producing step. The method for producing a carbon fiber filter according to claim 2, claim 3, claim 4, claim 5, claim 6, or claim 7. 9. The method according to claim 1, further comprising, prior to the sheet producing step, a carbon fiber proportion adjusting step in which the mixture has a carbon fiber content of not more than 85% by weight and not less than 55% by weight. 9. The method for producing a carbon fiber filter according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7, claim 7, or claim 8.