JP2008049295A - Coating-booth filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating-booth filter capable of simplifying a manufacturing step, preventing increase of pressure loss by a film-formation phenomenon of a molten resin, and preventing a waving of a filtering media by a thermal contraction ratio between fiber layers and formation of a wrinkle of a heat-bonding fiber sheet. <P>SOLUTION: The coating-booth filter 40 consists of a laminate of a short fiber layer 1 and a heat bonding fiber sheet 2 with a part of the respective fibers melted and thermally bonded. The short fiber layer 1 contains a mixed fiber of a high melting point fiber and the heat bonding fiber, and the heat-bonding fiber sheet 2 is a composite short fiber. Prior to thermal adhesion, a tension is given to the one having a small thermal contraction ratio of the short fiber layer 1 and the thermal bonding fiber sheet 2 to a degree of canceling a difference of the thermal contraction ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a paint booth filter for cleaning air supplied to a paint booth.

Conventionally, what was disclosed by patent document 1 as a filter for coating booths is known, for example. That is, a heat-fusible fiber sheet is coated on one side or both sides of a nonwoven fabric in which a short fiber layer is laminated in a single layer or a plurality of layers, and at least a part is fused and bonded. By using a non-woven fabric as the material, the initial pressure loss is low, the filtration performance is excellent, dust is collected sufficiently, the paint surface is not contaminated by the supply air, and the heat-fusible fiber sheet is used in combination. The adhesive effect by partial fusion prevents the fibers from falling off, and the surface is flat and smooth so that they can be handled easily and have characteristics suitable for painting booths.
JP 2005-111346 A

However, the prior art of Patent Document 1 has the following problems.
(1) According to the example disclosed in Patent Document 1, the short fiber layer is obtained by mixing the blended fibers and performing a carding process, a needling punch process, and heat-treating the fibers to bind the short fibers. Since the heat-fusible fiber sheet is laminated on the fiber layer and heat-treated to coat the surface, there is a problem that the heat treatment step is required twice.
(2) Further, if the heat treatment process is performed once and the manufacturing process is simplified, the heat-fusible fiber sheet of Patent Document 1, specifically, a low-melting polyester fiber sheet having a thin layer such as a web-like shape. Therefore, when heat-bonding with a heating roller, the fibers of the short fiber layer are bonded together and the short fiber layer and the heat-fusible fiber sheet are bonded at the same time. When heat is applied to all the fibers constituting the heat-fusible fiber sheet more than the heat energy required for bonding the fiber sheets, the heat-fusible fiber sheet may melt and become non-fibrous. . Conversely, when heat treatment is performed at a temperature at which the fiber state can be maintained, adhesion may not be sufficient.
(3) In addition, when the heat shrinkage rate of the short fiber layer and the heat-fusible fiber sheet is different, the layer with a small heat shrinkage rate cannot follow the change in the layer with a large heat shrinkage rate, and as shown in FIG. If the heat shrinkage rate of the short fiber layer 1 is smaller than that of the heat-fusible fiber sheet 2, there is a problem that the filter medium does not become flat and deforms like a wave. As shown in FIG. If the thermal shrinkage rate of No. 1 was larger than that of the heat-fusible fiber sheet 2, there was a problem that wrinkles were generated in the heat-fusible fiber sheet.
In FIG. 3, arrows indicated by A ′ and B ′ indicate the thermal shrinkage rates of the short fiber layer 1 and the heat-fusible fiber sheet 2, respectively, and in FIG. 4, A ″ and B ″. The arrows indicated by indicate the thermal shrinkage rates of the short fiber layer 1 and the heat-fusible fiber sheet 2, respectively.

  The present invention can simplify the manufacturing process with a single heat treatment step, prevent pressure loss improvement due to the melted resin film formation phenomenon, It aims at providing the filter for paint booths which prevented wrinkles.

As a result of intensive studies, the present inventors have found the following configuration in order to solve this problem. That is, the filter for a painting booth according to the present invention is for a painting booth in which a short fiber layer and a heat-fusible fiber sheet are laminated and a part of each fiber is melted and thermally bonded as described in claim 1. A filter, wherein the short fiber layer is a mixed fiber of high-melting fiber and heat-fusible fiber, and the heat-fusible fiber sheet is a composite short fiber, and before the heat bonding, these short fiber layers And a heat-fusible fiber sheet having a smaller heat shrinkage rate, tension is applied so as to offset the difference in heat shrinkage rate.
The paint booth filter according to claim 2 is the paint booth filter according to claim 1, wherein the difference between the thermal shrinkage rate of the short fiber layer and the thermal shrinkage rate of the heat-fusible fiber sheet is 10% or less. It is characterized by being.

The paint booth filter according to the present invention is a paint booth filter in which a short fiber layer and a heat-fusible fiber sheet are laminated and a part of each fiber is melted and thermally bonded. It is a mixed fiber of high melting point fiber and heat-fusible fiber, and the heat-fusible fiber sheet is a composite short fiber, and before the heat bonding, the heat-shrinkage of these short fiber layer and heat-fusible fiber sheet Because the tension is applied to the smaller ratio to offset the difference in thermal shrinkage, the fibers of the short fiber layer are bonded to each other, and the layers of the short fiber layer and the heat-fusible fiber sheet are bonded to each other. Since the bonding can be performed simultaneously, the manufacturing process can be simplified. As a result, the cost of the product can be reduced.
In addition, when the difference between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet is 10% or less, the heat shrinkage is performed even though there is a difference in heat shrinkage rate between both layers. In order to offset the difference in rate, tension is applied in advance to the one with the smaller heat shrinkage rate, so the heat shrinkage rate of each layer due to heat treatment is different, and the filter medium deforms like a wave instead of being flat. And the problem of wrinkling of the heat-fusible fiber sheet do not occur reliably.

Hereinafter, embodiments of the present invention will be described in detail.
For the short fiber layer of the present invention, a mixed fiber of a high-melting fiber and a heat-fusible fiber, particularly a heat-fusible composite fiber is used.
Examples of the high melting point fiber include synthetic fibers such as nylon resin, polyester resin, and polypropylene resin.
The heat-fusible fiber, particularly the heat-fusible composite fiber, has a core-sheath type and side-by-side type structure, and is, for example, any one of a polyester resin, a polyethylene resin, a polypropylene resin, and a polyamide resin. A fiber composed of a high melting point component and a low melting point component is used.
Specific examples include composite fibers of polyester fibers (melting point of about 250 to 270 ° C.) and low melting point polyester fibers (melting point of about 100 to 180 ° C.), polyester / nylon composite fibers, polyester / polyethylene composite fibers, polypropylene / polyethylene composite fibers. In particular, a composite fiber of a high-melting polyester and a low-melting polyester is most practical.

In this case, the melting point of the high melting point component constituting the composite fiber is preferably 50 ° C. or higher than the melting point of the low melting point component, and the melting point of the low melting point component is preferably in the range of 100 ° C. to 180 ° C.
If the melting point of the high melting point component is higher than the melting point of the low melting point component only by a temperature difference of less than 50 ° C., the high melting point fiber side is also softened when the short fibers are bonded, and a desired filter cannot be obtained. Moreover, when the melting point of the low melting point component is less than 100 ° C., the treatment conditions for carrying out adhesion between fibers are difficult, which is not preferable from the viewpoint of heat resistance. In addition, if the melting point of the low melting point component exceeds 180 ° C., it affects the thermal characteristics of the high melting point fiber, and the filter characteristics vary due to the bonding, which is not preferable.

  The fineness is preferably in the range of 1 to 100 dtex. If the fineness is less than 1 dtex, a sufficiently bulky filter having filtration performance cannot be obtained. On the other hand, when the fineness exceeds 100 dtex, the number of fibers is reduced and the inter-fiber adhesion point is also reduced to obtain bulkiness, but a filter having desired filtration performance cannot be obtained.

Further, in the range basis weight mass of 100g / m ² ~500g / m ² of the short fiber layer, and in the configuration 40 to 85 wt% of the high melting point fibers (construction 60-15 wt% of the composite fiber) It is effective.
If the mass per unit area is less than 100 g / m ² , satisfactory filtration performance cannot be obtained, and even if it is satisfactory, the filtration life is shortened. On the other hand, when it exceeds 500 g / m ² , it is difficult to obtain a low initial pressure loss.
Further, when the composition of the high melting point fiber is less than 40% by mass, that is, when the composite fiber exceeds 60% by mass, the bulkiness (thickness is difficult to obtain) is poor, and it is difficult to obtain a filter with low initial pressure loss. On the contrary, when it exceeds 85 mass%, since there are few composite fibers, even if a bulky filter is obtained, it will lose shape immediately and will fall. Further, short fibers are likely to come off, which is not preferable.
In order to obtain a bulky filter while maintaining the thickness, the thickness is preferably in the range of 15 mm to 30 mm. To ensure bulkiness in this range, in the case of a single layer, the high melting point fiber and the composite fiber In order to ensure the thickness and filtration performance of mixed fibers, the fineness composition of high melting point fiber is easy to achieve with the combination of thick and fine, and to obtain a filter with high filtration performance with low initial pressure loss by combining thick and fine fineness The conditions can be adjusted.

  The mixing ratio of thick and fine fibers is appropriately determined depending on the thickness and filtration performance. In the case of lamination, it is obtained by laminating these thick and thin high-melting fiber layers with a mixed fiber layer of thick high-melting fibers and heat-fusible fibers, and a thin fiber mixture of high-melting-point fibers and heat-fusible fibers. It is done. And in lamination | stacking, let the fineness side be a rough layer, and let the fineness side be a dense layer. In order to ensure the thickness and filtration performance, the ratio of the thick and thin fiber layers may be determined, and the fineness range is determined in the same manner as in the case of a single layer. The lamination ratio of thick and fine fibers is appropriately determined depending on the thickness and filtration performance.

  The heat-fusible fiber sheet that is coated on the short fiber layer is a composite that adheres the heat-fusible fiber sheet to the surface of the bulky short fiber layer and prevents the short fibers in the short fiber layer from coming off. As the fiber, a core-sheath type or side-by-side type structure, for example, a fiber composed of a high melting point component and a low melting point component of any one of a polyester resin, a polyethylene resin, a polypropylene resin, and a polyamide resin is used. It is done. Specific examples include composite fibers of polyester fibers (melting point of about 250 to 270 ° C.) and low melting point polyester fibers (melting point of about 100 to 180 ° C.), polyester / nylon composite fibers, polyester / polyethylene composite fibers, polypropylene / polyethylene composite fibers. In particular, a composite fiber of a high-melting polyester and a low-melting polyester is most practical.

In this case, the melting point of the high melting point component constituting the composite fiber is preferably 50 ° C. or more higher than the melting point of the low melting point component, and the melting point of the low melting point component is preferably in the range of 100 ° C. to 180 ° C.
If the melting point of the high melting point component is higher than the melting point of the low melting point component only in the range of less than 50 ° C., the high melting point fiber side is softened at the time of bonding between the short fibers, and a desired filter cannot be obtained. Further, if the melting point of the low melting point component is less than 100 ° C., the treatment conditions for carrying out adhesion with the short fiber layer are difficult, which is not preferable from the viewpoint of heat resistance. When the melting point of the low melting point component exceeds 180 ° C., the characteristics of the surface of the short fiber layer change, and the fluctuation of the filter characteristics increases by performing the adhesion.

Basis weight mass of the heat-fusible fiber sheet is preferably in the range of ^{10g / m 2 ~100g / m 2} , although it is not impair the filtration performance is less than 10 g / m ^2, the hair of the short fiber layer removal prevention This is not preferable because (fiber scattering prevention) cannot be sufficiently prevented. On the other hand, if it exceeds 100 g / m ² , the hair loss of the short fiber layer is sufficient, but the resistance on the surface on the outflow side increases, so that it is difficult to obtain a low initial pressure loss.

By preliminarily compressing the heat-fusible fiber sheet with a roller while heating, the surface smoothness of the filter medium comprising the short fiber layer and the heat-fusible fiber sheet can be improved. Further, after the short fiber layer and the heat-fusible fiber sheet are bonded to each other, the surface smoothness is also improved by heat-treating the surface of the heat-fusible fiber sheet with a heating roller or a heating plate. be able to.
Moreover, in order to impart the flame retardancy of the filter, it can be coated with a resin solution containing a flame retardant after the filter is produced, or a flame retardant such as nitrogen, bromine, chlorine or phosphorus can be kneaded into the fiber. . However, it is preferable to use a non-halogen flame retardant in consideration of the influence on the human body and the environment.

The difference between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet is preferably 10% or less. If the difference in heat shrinkage rate exceeds 10%, it becomes difficult to adjust the offset of the heat shrinkage rate difference by previously applying tension to the smaller heat shrinkage rate.
As a method for applying tension in advance to the one having a smaller heat shrinkage rate, for example, the supply line for the short fiber layer and the heat fusible fiber sheet supply line are separated, and the tension on the supply line side having the smaller heat shrinkage rate is provided. Can be adjusted easily by raising
For example, when the heat shrinkage rate of the heat-fusible fiber sheet is small, as shown in FIG. 1, the heat shrinkage rate of the short fiber layer 1 and the heat-fusible fiber sheet 2 are previously set on the heat-fusible fiber sheet 2. By applying the tension of the difference in the heat shrinkage rate, the difference in the heat shrinkage rate and the shrinkage due to the restoration of the heat fusible fiber sheet are offset when heated, and the heat fusible fiber sheet is wrinkled. It can be prevented from occurring.
In FIG. 1 and FIG. 4, arrows indicated by A and B respectively indicate the thermal shrinkage rates of the short fiber layer 1 and the heat-fusible fiber sheet 2, and AB indicates the short fiber layer 1. The difference of the heat shrinkage rate of the heat-fusible fiber sheet 2 is typically represented.

  Hereinafter, specific examples of the present invention will be described.

(Example 1)
As shown in FIG. 2, the core-sheath polyester composite fiber having a fineness of 17 dtex and a fiber length of 76 mm (melting point of the core polyester: 265 ° C., melting point of the sheath polyester: 110 ° C.) is 40% by mass, the fineness is 4.4 dtex, and the fiber length is 51 mm. 1 mm thickness obtained by uniformly mixing 60% by mass of the core-sheath polyester conjugate fiber (melting point of core polyester: 265 ° C., melting point of sheath polyester: 110 ° C.), weight per unit area 25 g / m ² , heat shrinkage 0 % Of the heat-fusible fiber sheet 2 is unwound from the supply roll 10 and wound around the take-up roll 11 to give a difference in tension between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet. However, it was conveyed by the conveyors 21 and 22. At the same time, 75% by mass of a flame-retardant polyester short fiber having a fineness of 6.6 dtex, a fiber length of 64 mm, and a melting point of 265 ° C., and a core-sheath polyester composite fiber having a fineness of 2.2 dtex and a fiber length of 64 mm (melting point of the core polyester: 265). The melting point of the polyester at the sheath and the melting point of the sheath polyester: 110 ° C.) is uniformly mixed with a carding machine 30 and then needle-punched with a needling machine 31 from the outflow side when the filter is used. The short fiber layer 1 having a heat shrinkage rate of 6%, which is processed to make the outflow side dense and have a coarse and dense structure, is stacked on the heat-fusible fiber sheet 2 and conveyed by the conveyors 20, 21, and 22. did. The filter medium obtained by laminating the short fiber layer 1 and the heat-fusible fiber sheet 2 is continuously heat-treated with a heat treatment machine (hot air through method) 32 at a temperature of 160 ° C. and a residence time of 3 minutes, and the fibers of the short fiber layer are bonded to each other. And the surface of the short fiber layer was covered with the heat-fusible fiber sheet to obtain a coating booth filter 40 having a thickness of 20 mm and a mass per unit area of 325 g / m ² .

(Example 2)
A core-sheath polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of core polyester: 265 ° C., melting point of sheath polyester: 150 ° C.) is uniformly mixed to a thickness of 1 mm, weight per unit area of 20 g / m ² , heat While rewinding the heat-fusible fiber sheet 2 having a shrinkage rate of 0% from the supply roll 10 and winding it on the take-up roll 11, the difference between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet is calculated. It was made to convey with the conveyors 21 and 22, applying tension | tensile_strength. At the same time, 40% by mass of polyester short fibers having a fineness of 6.6 dtex, a fiber length of 64 mm, and a melting point of 265 ° C., a fineness of 1.45 dtex, a fiber length of 64 mm, and 35% by mass of polyester short fibers having a melting point of 265 ° C., and a fineness of 2.2 dtex. A carded processing machine 30 is used to uniformly mix 25% by mass of a core-sheath polyester composite fiber having a fiber length of 64 mm (melting point of core polyester: 265 ° C., melting point of sheath polyester: 110 ° C.). Next, a short fiber layer having a heat shrinkage rate of 6% is formed on the heat-fusible fiber sheet 2 from the outflow side when the filter is used by the needling machine 31 with a needle punching process to make the outflow side dense and have a dense structure. It was made to convey with conveyor 20,21,22. The filter medium obtained by laminating the short fiber layer 1 and the heat-fusible fiber sheet 2 is continuously heat-treated with a heat treatment machine (hot air through method) 33 at a temperature of 180 ° C. and a residence time of 3 minutes. And the surface of the short fiber layer was covered with the heat-fusible fiber sheet to obtain a coating booth filter 40 having a thickness of 20 mm and a weight per unit area of 274 g / m ² .

Example 3
Core-sheath polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of core polyester: 265 ° C., melting point of sheath polyester: 110 ° C.) 40% by mass, core-sheath polyester composite fiber having a fineness of 13 dtex and fiber length of 64 mm (The melting point of the core polyester: 265 ° C., the melting point of the sheath polyester: 110 ° C.) 60% by mass uniformly mixed, a heat-fusible fiber sheet having a thickness of 1 mm, a mass per unit area of 25 g / m ² , and a heat shrinkage rate of 0% 2 while rewinding 2 from the supply roll 10 and winding it around the take-up roll 11, while applying the tension of the difference between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet, It was made to convey. At the same time, a polyester short fiber having a fineness of 33 dtex, a fiber length of 64 mm and a melting point of 265 ° C., 30% by mass, a fineness of 9 dtex, a fiber length of 64 mm, and a polyester short fiber of 20% by mass of a melting point of 265 ° C. 50% by mass of sheath polyester conjugate fiber (melting point of core polyester: 265 ° C., melting point of sheath polyester: 110 ° C.) of 50% by mass is subjected to carding with a carding machine 30 and then used as a filter. From the outflow side, a short fiber layer having a heat shrinkage ratio of 6%, which is subjected to needle punching by the needling machine 31 to make the outflow side dense and a coarse-dense structure, is overlaid on the heat-fusible fiber sheet 2, It was made to convey with the conveyors 20, 21, and 22. The filter media obtained by laminating the short fiber layer 1 and the heat-fusible fiber sheet 2 are continuously heat-treated with a heat treatment machine (hot air through method) 33 at a temperature of 160 ° C. and a residence time of 3 minutes. And the surface of the short fiber layer was coated with the heat-fusible fiber sheet to obtain a coating booth filter having a thickness of 18 mm and a mass per unit area of 430 g / m ² .

(Comparative Example 1)
A thickness of 20 mm is obtained in the same manner as in Example 1 except that the heat-fusible fiber sheet is not imparted with the tension of the difference between the heat shrinkage rate of the short fiber layer and the heat shrinkage rate of the heat-fusible fiber sheet. A filter for a coating booth having a basis weight of 311 g / m ² was obtained.

(Conventional example)
80% by mass of polyester short fibers having a fineness of 6.6 dtex, fiber length of 64 mm and melting point of 265 ° C., core-sheath polyester composite fiber having a fineness of 2.2 dtex and fiber length of 64 mm (melting point of core polyester: 265 ° C., melting point of sheath polyester) : 110 ° C) 20% by mass is uniformly mixed and carded, then needle punched from the outflow side when using the filter to make the outflow side dense and a dense structure with a short fiber layer with a heat shrinkage of 6% did.
Further, a heat-fusible fiber sheet made of a spunbonded nonwoven fabric having a web-like melting point of 115 ° C. and a basis weight of 25 g / m ² was prepared.
Next, a filter medium in which the heat-fusible fiber sheet is laminated on the surface of the short fiber layer (the surface into which the needle has entered during needle punching) is continuously heated at 160 ° C. with a heat treatment machine (hot air-through method). A coating booth having a thickness of 20 mm and a mass per unit area of 320 g / m ² , wherein the fibers of the short fiber layer are bonded by heat treatment for a residence time of 3 minutes and the surface of the short fiber layer is coated with the heat-fusible fiber sheet. A filter was obtained.

The characteristics of the short fiber layer and the heat-fusible fiber sheet of the above examples, comparative examples and conventional examples were measured by the following method. That is, the fineness was measured according to JIS L1015, the fiber length was measured according to JIS L1015, the melting point was measured according to JIS L1015, the thickness was measured according to the method described in 8.5.1 of JIS L1096, and the basis weight was 8 according to JIS L1096. Measured according to the method described in 4.2. In addition, the thermal shrinkage ratio is determined by measuring the dimension in the width direction (the direction that becomes the width direction during production) after leaving the sample in the oven at the same temperature as the heat treatment for the same residence time as the shrinkage with respect to the original dimension. The ratio of dimensional change was determined and used as the heat shrinkage rate (%).
The filter media smoothness (whether wrinkles and undulations were present) of the filters obtained in the above Examples, Comparative Examples, and Conventional Examples was evaluated visually by the presence or absence of wrinkles and undulations after heat treatment.

  In all of Examples 1 to 3, no wrinkle or undulation phenomenon occurred, and the filter medium smoothness was excellent. On the other hand, in the conventional example, the fibers of the heat-fusible fiber sheet melt as a whole and become no longer fibrous, and in the comparative example, wrinkles of the heat-fusible fiber sheet occur and the filter medium smoothness is poor. Met.

  Since the present invention is an air filter that prevents fiber scattering due to fiber dropping during use, and does not have a defective appearance of the filter such as wrinkle generation and wavy deformation even if the manufacturing process is simplified, it is particularly suitable for automobile air conditioning such as a painting booth. The present invention has industrial applicability in that it has advantages when used in the industry.

Sectional drawing which shows the state before and behind the heating of the air filter of this invention Schematic diagram showing the manufacturing process of the air filter of the present invention Sectional drawing which shows the state before and behind the heating of the conventional air filter Sectional drawing which shows the state before and behind the heating of the conventional air filter

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Short fiber layer 2 Heat-fusible fiber sheet 10 Supply roll 11 Winding roll 20 Conveyor 21 Conveyor 22 Conveyor 30 Carding machine 31 Needling machine 32 Heat treatment machine 40 Filter for coating booth A Thermal contraction rate of short fiber layer B Thermal shrinkage ratio AB of heat-fusible fiber sheet Difference in thermal shrinkage ratio between short fiber layer and heat-fusible fiber sheet

Claims (2)

  A filter for a coating booth in which a short fiber layer and a heat-fusible fiber sheet are laminated and a part of each fiber is melted and thermally bonded, and the short fiber layer is a high-melting fiber and a heat-fusible fiber. The heat-fusible fiber sheet is a composite short fiber, and before the heat bonding, the heat shrinkage rate is smaller in the smaller one of the heat shrinkage rate of the short fiber layer and the heat-fusible fiber sheet. A coating booth filter, wherein tension is applied so as to cancel out the difference between the two.   The coating booth filter according to claim 1, wherein a difference between the thermal shrinkage rate of the short fiber layer and the thermal shrinkage rate of the heat-fusible fiber sheet is 10% or less.

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