JP2001248056A - Composite filament nonwoven fabric and filter obtained therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite filament nonwoven fabric for a filter, having higher properties for collecting powder dust and excellent in pleating property as an air filter use requiring the high collecting properties. SOLUTION: This composite filament nonwoven fabric is characterized in that the composite filament nonwoven fabric is obtained by laminating a filament nonwoven fabric composed from a polymer with the low melting point to a filament nonwoven fabric including an ultrafine fiber, and thermally bonding the nonwoven fabrics by the fusion or the softening of the polymer with the low melting point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite long-fiber non-woven fabric, and more particularly to a composite long-fiber non-woven fabric which is excellent in dust collecting property and pleating characteristics and is suitable for use in filters, and a filter comprising the composite long-fiber non-woven fabric. Things.

[0002]

2. Description of the Related Art In the field of advanced technologies such as semiconductors, it is well known that fine particles suspended in the air and fine particles contained in pure water, solvents, chemicals, and the like cause defective products. In these manufacturing plants, an air filter is used to maintain an extremely clean air environment, and plays an important role in determining cleanliness. Various air filters of different grades are used in each stage from the outside air intake to the air outlet to the room, and these air filters mostly use a fiber layer filter medium.

However, in recent years, a filter made of a long-fiber nonwoven fabric having excellent durability and workability has been used in place of a filter material for a fiber layer.
Is disclosed. This technology is based on a blending method using polyethylene terephthalate as the high melting point component and copolymerized polyester as the low melting point component, or a core-sheath type composite method where the core component is a high melting point component and the sheath component is a low melting point component. And embossed. However, since it is composed of filaments in the range of 1 to 10 denier, there is a disadvantage that small particles are difficult to be collected. Therefore, it is not suitable for an air filter that requires high collection performance.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention solves the above-mentioned drawbacks of the filter equipment, and provides a composite long-fiber nonwoven fabric for a filter having higher collecting performance and excellent pleating workability. What you want to do.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides a long-fiber nonwoven fabric A comprising a low-melting polymer.
1 and a long-fiber nonwoven fabric B containing ultrafine fibers are laminated and thermally bonded by melting or softening of a low-melting polymer, and a composite long-fiber nonwoven fabric is characterized.

Further, the present invention is characterized in that a long-fiber nonwoven fabric A2 composed of a low-melting polymer and a high-melting polymer and a long-fiber nonwoven fabric B containing ultrafine fibers are laminated and thermally bonded by melting or softening of the low-melting polymer. SUMMARY OF THE INVENTION

Further, the present invention provides a filter characterized by comprising the above-mentioned composite long-fiber nonwoven fabric.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polymers constituting the long-fiber nonwoven fabric A1, long-fiber nonwoven fabric A2 and long-fiber nonwoven fabric B in the present invention include polyester-based polymers, polyamide-based polymers, and polyolefin-based polymers.

Examples of the polyester polymer include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalene-2,6-dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and esters thereof. And a homopolyester polymer or copolymer containing a diol compound such as ethylene glycol, diethylene glycol, 1,4-butadiol, neopentyl glycol, cyclohexane-1,4-dimethanol as an ester component. In addition, paraoxybenzoic acid, 5-sodium sulfoisophthalic acid, polyalkylene glycol, pentaerythritol, bisphenol A, and the like may be added or copolymerized to these polyester polymers.

Examples of the polyamide polymer include polyimino-1-oxotetramethylene (nylon 4), polytetramethylene adivamide (nylon 46), polycapramid (nylon 6), polyhexamethylene adivamide (nylon 66), polyundene Kanaamide (nylon 11),
Examples thereof include polyurolactamide (nylon 12), polymethaxylene adibamide, polyparaxylylene decanamide, polybiscyclohexyl methane decanamide, and a polyamide-based polymer having these monomers as constituent units. In particular, in the case of polytetramethylene adibamide (nylon 46), the polyamide component such as polycapramid, polyhexamethylene adibamide, polyundecamethylene terephthalamide is not more than 30 mol% in polytetramethylene adibamide (nylon 46). May be a copolymerization of polytetramethylene adibamide copolymerized with the above. When the copolymerization ratio of the polyamide component exceeds 30 mol%, the melting point of the copolymer decreases, and thus the nonwoven fabric composed of these copolymers is not suitable for use at high temperatures.

Examples of the polyolefin polymer include aliphatic α-monoolefins having 2 to 18 carbon atoms, for example, ethylene, propylene, 1-butene, 1-pentene, 1.3.
And polyolefin polymers comprising -methylbutene, 1-hexene, 1-octene, 1-octadecene. These aliphatic α-monoolefins contain many ethylenically unsaturated monomers such as butadiene, isopropylene,
A polyolefin copolymer obtained by copolymerizing a similar ethylenically unsaturated monomer such as 1.3-pentadiene or styrene α-methylstyrene may be used. In the case of a polyethylene copolymer, ethylene is copolymerized with propylene, 1-butene, 1-octene, 1-hexene, or a similar higher α-olefin in an amount of 10% by weight or less. Is also good. In the case of a polypropylene-based polymer, propylene may be copolymerized with ethylene or a similar higher α-olefin by 10% by weight or less, but the copolymerization ratio of these copolymers is not more than 10% by weight. If the content is more than 10% by weight, the melting point of the copolymer decreases, and the nonwoven fabric composed of these copolymers is not suitable for use at high temperatures.

[0013] The long-fiber nonwoven fabric used in the present invention is composed of the above-mentioned polymer having a fiber-forming property, and two or more different polymers selected from the above-mentioned polymers are each melt-spun. It may be composed of a blend blended within a range that does not impair the properties. If necessary, various additives such as a matting agent, a pigment, a flame retardant, a deodorant, a light stabilizer, a heat stabilizer, an antioxidant, and a crystallization accelerator may be added to the polymer according to the present invention. May be added in a range that does not impair the purpose.

The long-fiber nonwoven fabric A1 or long-fiber nonwoven fabric A2 in the present invention comprises a low-melting polymer as a constituent polymer. When the low-melting polymer is laminated and integrated with the long-fiber nonwoven fabric B, it is melted or softened by heat, and serves as an adhesive for bonding the two long-fiber nonwoven fabrics. The low-melting polymer is a high-melting polymer, a long-fiber nonwoven fabric B constituting the long-fiber nonwoven fabric A2.
Has a melting point or softening point lower than the melting point of the polymer constituting the microfibers, and preferably has a melting point or softening point lower by 20 ° C. or more. If there is no difference between the melting point or softening point of the low melting point polymer and the melting point of the high melting point polymer and the melting point of the polymer constituting the ultrafine fibers, the long fiber nonwoven fabric A1 or A2 and the long fiber nonwoven fabric B are joined. During the heat treatment, not only the low-melting polymer, but also the high-melting polymer and the polymer constituting the ultrafine fibers are melted or softened, and the entire composite long-fiber nonwoven fabric becomes resin. If the non-woven fabric is not obtained, and the ultrafine fibers adhere to each other by melting, it is not possible to obtain a composite non-woven fabric having the fine inter-fiber voids, which is the object of the present invention.

The long-fiber nonwoven fabric A2 is made of a low-melting polymer and a high-melting polymer. For example, long fibers made of a low-melting polymer and long fibers made of a high-melting polymer are mixed. Long-fiber nonwoven fabrics, and long-fiber nonwoven fabrics composed of cross-section composite long fibers in which a low-melting-point polymer forms a part of the fiber surface (including cross-sectional shapes such as a bonded type, a core-sheath type, and a split type). And the like. Among them, it is preferable to use a long-fiber nonwoven fabric made of a core-in-sheath composite fiber in which a high-melting polymer is provided in a core portion and a low-melting polymer is provided in a sheath portion. The combination of the high melting point polymer and the low melting point polymer constituting the long fiber nonwoven fabric A2 is not particularly limited as long as it has the above-described melting point difference.

The single fiber fineness of the constituent fibers of the long-fiber nonwoven fabric A1 or A2 is preferably 2 to 17 dtex. If it exceeds 17 dtex, it is not preferable because the yarn is insufficiently cooled, the fiber is hardly opened, and the operability is deteriorated. Further, if less than 2 dtex, the rigidity of the fiber is inferior, so when the obtained composite long fiber nonwoven fabric is used as a filter,
It is not preferable because the pleating property is not good.

The long-fiber nonwoven fabric A1 or A2 can be obtained by a known spunbonding method. That is, the thermoplastic polymer constituting the long-fiber nonwoven fabric A1 or A2 is melted, and long fibers are spun from the die. The spun filaments are cooled using a known cooling device, and then drawn and thinned to a target fineness using an air sucker, and then taken out. The towing speed is 2500 m / min or more, preferably 3000 m / min or more. The drawn and thinned filaments are spread by a conventionally known spreading device, and then spread and deposited on a movable collecting surface such as a screen conveyor to form a filament web. By applying heat or pressure to the obtained long-fiber web, or by performing entanglement treatment, the form is maintained to obtain a long-fiber nonwoven fabric A1 or A2. In addition, in the state of the long fiber web, it is laminated with the long fiber nonwoven fabric B,
By heat treatment, the fibers are bonded and integrated with the long-fiber nonwoven fabric B, and the constituent fibers of the long-fiber web A1 or A2 are heat-bonded to each other by melting or softening the low-melting polymer to maintain the form. Good.

The long-fiber nonwoven fabric B contains ultrafine fibers. In the present invention, the ultrafine fiber refers to a fiber having a single yarn fineness of 0.6 decitex or less. When the long-fiber nonwoven fabric B contains such ultrafine fibers, the dust collection efficiency can be improved.

As a method of obtaining such a long-fiber nonwoven fabric containing ultrafine fibers, a method of obtaining a web by a melt blow method or a direct spinning method to form a nonwoven fabric, a method of using a sea-island type bicomponent composite long fiber, A method of obtaining an extra-fine long-fiber nonwoven fabric composed of islands by melting or breaking by impact, using a web made of splittable conjugate fibers, giving a physical impact and splitting to express extra-fine fibers A method of forming a long-fiber non-woven fabric may be used. In the present invention, it is preferable to use a long-fiber nonwoven fabric in which ultrafine fibers are developed by dividing using a web made of splittable conjugate fibers in consideration of yarnmaking operability and productivity.

As the splittable conjugate long fiber, one composed of two or more kinds of incompatible polymers is used. The incompatibility with each other is to make the splittable conjugate long fibers easy to split when subjected to impact. Examples of the splitting method for splitting include a needle punching method and a spunlace method. Alternatively, the fibers may be split using a microcreper (buckling machine) manufactured by Micrex Corporation. The splitting treatment is performed using a long-fiber nonwoven fabric A1 or A2
Before or after heat treatment after lamination. When the splitting treatment is performed in the state of the web before the heat treatment, the constituent fibers of the long-fiber nonwoven fabric B are three-dimensionally entangled. Furthermore, long fiber nonwoven fabric A
When lamination with 1 or A2 is performed before the heat treatment, the constituent fibers near the lamination boundary surface of the nonwoven fabric are entangled and integrated by the action of needle punch or spunlace,
The constituent fibers of the long fiber nonwoven fabric B are three-dimensionally entangled. The long-fiber nonwoven fabric B, in which the constituent fibers are three-dimensionally entangled, has a moderately dense interfiber space and is excellent in collecting fine dust. In addition, when performing splitting treatment after heat treatment, since the fibers are fixed by thermal bonding, the splitting tends to be performed without entanglement, so that the gap between the ultrafine fibers is entangled. It is a big thing compared with. Therefore, the dust collection capacity increases. Also, in filter applications such as bag filters, once the collected dust mass is removed by vibration or air, etc., when used for recycling, it has a moderately large inter-fiber space so that dust mass can be easily removed and recycled It will have excellent properties.

FIG. 1 shows a specific example of the splittable conjugate long fiber.
2 having a cross section as shown in FIG. These are forms in which both components of the polymer that are incompatible with each other are exposed on the surface of the fiber, and within the cross section of the fiber, one polymer component can be split and split by the other polymer component. It is divided into.

The splittable conjugate long fibers are split at the boundary between both polymer components by split splitting treatment, and develop ultrafine fibers. The single-fiber fineness of the ultrafine fibers to be expressed is 0.6 dtex or less, and more preferably 0.06 to 0.6 dtex. If the single-fiber fineness is less than 0.06 dtex, spinning is practically difficult, and it is difficult to obtain a split type composite long fiber at low cost and rationally. In addition, there is a tendency that it is difficult to sufficiently perform split splitting.

In the present invention, examples of the combination of the two polymers constituting the splittable conjugate long fiber include polyolefin / polyamide, polyolefin / polyester, polyamide / polyester and the like. Various combinations of are also arbitrarily adopted.

The long-fiber nonwoven fabric B has a single-fiber fineness of 0.1.
In addition to the ultrafine fibers of 6 decitex or less, other fibers other than the ultrafine fibers may be contained as long as the object of the present invention is not impaired. The single yarn fineness of other fibers other than this ultrafine fiber is
It is preferably 2.2 dtex or less. 2.2
Exceeding the decitex is not preferable because the voids between the fibers constituting the long-fiber nonwoven fabric B become large and the dust collecting performance is poor.

When the constituent polymer of the ultrafine fibers or the fibers other than the ultrafine fibers is made of a polymer having the same or compatibility as the low melting point polymer constituting the long-fiber nonwoven fabric A1 or A2, the low melting point It is preferable because it has excellent adhesiveness at the time of thermal bonding / integration by melting or softening of the polymer, and has the effects of improving pleating workability in filter applications and increasing the inter-fiber voids.

The lamination ratio (% by weight) of the long-fiber nonwoven fabric A1 or A2 and the long-fiber nonwoven fabric B is not particularly limited.
When used as a filter, 70/30 to 20 /
It is preferably within the range of 80. If the lamination ratio of the long-fiber nonwoven fabric B is less than 30% by weight, the dust collecting performance tends to be inferior. On the other hand, if it exceeds 80% by weight, the rigidity of the obtained composite long-fiber nonwoven fabric is insufficient, resulting in poor pleating property. Inferior.

The basis weight of the composite long-fiber nonwoven fabric of the present invention is not particularly limited.
It is preferably at least 0 g / m ² . Weight is 100g
If it is less than / m ² , the degree of dense overlap between the long fibers is low, and the mechanical performance and the formation of the obtained composite long-fiber nonwoven fabric tend to decrease, and dust collecting property unevenness due to the weight unevenness occurs. Therefore, it is not preferable. On the other hand, the upper limit of the basis weight is preferably about 500 g / m ² in consideration of pleating workability and avoiding excessive quality.

The composite long-fiber nonwoven fabric is formed by laminating long-fiber nonwoven fabrics A1 or A2 and long-fiber nonwoven fabric B, and is heat-bonded by melting or softening the low-melting polymer constituting the long-fiber nonwoven fabrics A1 or A2 to be integrated. I have. Examples of the method of heat bonding include a hot air circulation method using dry heat, a wet heat method using heating steam, a method of performing a partial thermocompression bonding through an embossing device or the like, and a method of performing a partial heat bonding through an ultrasonic welding machine. A method of fusing can be effectively used. By this heat bonding, the laminated long-fiber nonwoven fabric is integrated, and the low-melting-point polymer is melted or softened to be resinified. Therefore, the resulting composite nonwoven fabric is
It has moderate rigidity and good pleating workability.

When using the hot air circulation system, the temperature of the hot air is determined by the melting point of the low-melting polymer (the one having no melting point has a softening point).
It is preferable that the temperature be slightly higher, that is, 5 to 20 ° C. higher than the melting point. If the temperature is lower than (melting point + 5 ° C.), the low-melting polymer does not melt or soften sufficiently, so that the two long-fiber nonwoven fabrics are not sufficiently bonded and fixed.
On the other hand, if the temperature is higher than (melting point + 20 ° C.), polymers other than the low melting point polymer may be melted and softened, which is not preferable.

As a heating steam, an apparatus capable of applying pressure can be used for effective lamination and integration.
The temperature of the steam depends on the pressure in the heating steam device, but may be set in the range of the melting point of the low melting point polymer (the softening point is the one having no melting point) to (melting point +10) ° C.

In the case of using an embossing device, a portion that passes through a known embossing device including an embossing roll and a flat roll or an embossing device including a pair of embossing rolls and contacts an engraved pattern (convex portion) of the embossing roll. Is melted or softened to thermally fuse the constituent fibers together to form a partial thermocompression bonding portion. The roll temperature is set to a temperature lower than the melting point of the low-melting polymer (softening point is a polymer having no melting point). If the roll temperature is equal to or higher than the melting point of the low-melting polymer, the melted resin adheres to the roll and the operability is significantly impaired.

The partial thermocompression bonding portion has an area of 10 to 30%, preferably 10 to 20% with respect to the total surface area of the composite nonwoven fabric, and the area of each thermocompression bonding portion is 0.1 to 1.0 mm ^2. ,
The density of the crimping portion is 4 to 80 pieces / cm ² , preferably 10
Preferably, it is 60 to 60 particles / cm ² . The area of the partial thermocompression bonding part is less than 10%, or the density of the pressure contact part is 4 pieces / c.
When it is less than m ² , the mechanical properties and shape retention of the composite long-fiber nonwoven fabric are not improved, while the area of the partially thermocompression-bonded portion is 3
If it exceeds 0%, or if the pressure contact density exceeds 80 pcs / cm ² , the interfiber space becomes too small, and when used as a filter, clogging due to the particles collected immediately occurs, and over a long period of time. It cannot be used.

[0033]

Next, the present invention will be described with reference to examples, but the present invention is not limited to the examples. In the examples, the measurement of each characteristic value was performed by the following method.

(1) Melting point (° C.) Maximum value of a melting endothermic curve obtained by measuring with a sample weight of 5 mg and a heating rate of 20 ° C./minute using a differential calorimeter DSC-2 type manufactured by PerkinElmer. Was given as the melting point.

(2) Melt index (hereinafter abbreviated as MI) Measured according to the method described in ASTM-D-1238 (E).

(3) Melt flow rate (hereinafter referred to as MFR)
Abbreviated. ) Measured according to the method described in ASTM-D-1238 (L).

(4) Relative viscosity (a) The relative viscosity of polyethylene terephthalate was measured by the following method. A mixed solution of phenol and ethane tetrachloride was used as a solvent, and 0.5 g of a sample was dissolved in 100 cc of the solvent.

(5) Relative viscosity (b) The relative viscosity of polycapramide (nylon 6) was measured by the following method. A sample (1 g) was dissolved in 96% sulfuric acid (100 cc) and measured by a conventional method at a temperature of 25 ° C.

(6) Weight of nonwoven fabric (g / m ² ) Ten samples of 10 cm long × 10 cm wide were prepared from the sample in the standard state, and the equilibrium moisture content was set. Then, the weight (g) of each sample was obtained. Was weighed, and the average value of the obtained values was converted to the unit area to obtain the basis weight (g / m ² ).

(7) Air permeability of the nonwoven fabric (cm ³ / cm ² /
(Second) Measured according to the method described in JIS-L-1096, 6.27.1A method. That is, a total of 10 sample pieces each having a sample length of 15 cm and a sample width of 15 cm were prepared, the amount of air passing through the test piece was determined for each sample piece using a Frazier-type tester, and the average value was calculated as the air permeability ( cm ³ / cm ² / sec).

(8) Dust Collection Efficiency (%) A total of five sample pieces each having a sample length of 20 cm and a sample width of 20 cm were prepared, and a latex dust having an average particle diameter of 0.5 μm was collected.
Air containing a concentration of 5 mg / m ³ is passed through a cylinder having an inner diameter of 110 mm at a wind speed of 6.0 m / min, and before and after each sample piece stretched in this cylinder so as to block the air flow. The dust concentration in the air is measured by a forward scattering light receiving type digital display dust meter using an optical laser diode as a light source. Then, the dust concentration before passing through the sample piece (A) and the dust concentration after passing through the sample piece (B) are measured to four decimal places, the collection efficiency is measured by the following equation, and the average value is taken as the dust collection efficiency. (%). Dust collection efficiency (%) = [(AB) / A] × 100

(9) Pressure loss (KPa) The pressure before and after passing the sample piece before and after the sample piece at the time of measuring the dust collection efficiency is measured to one decimal place, and the average of the pressure difference is measured. The value was defined as pressure loss (KPa).

(10) Compression Bending Softness (N) A total of five sample pieces each having a sample length of 10 cm and a sample width of 5 cm were prepared, and each of the sample pieces was bent in the lateral direction to form a cylindrical object. The joined part was used as a measurement sample. Next, a constant-speed elongation type tensile tester (Tensilon RTM-50 manufactured by Toyo Baldwin Co., Ltd.) was used for each measurement sample in the axial direction.
Using (0), compression was performed at a compression speed of 5 cm / min, and the average value of the obtained maximum load values (N) was defined as compression stiffness (N).

(11) Pleating workability A sample having a width of 100 cm and a length of 300 m was bent by a rotary pleating machine, pleated so as to have a pitch of 25 mm, and evaluated according to the following criteria. ：: Pleated or sharp and uniform. Δ: Pleat is slightly uneven. X: The pleats are uneven and there is a problem in processing.

Example 1 A long-fiber nonwoven fabric A2 was produced by a spunbond method using a polyethylene polymer having a melting point of 130 ° C. and MI = 20 g / 10 min, and a polyethylene terephthalate polymer having a melting point of 255 ° C. and a relative viscosity of 1.38. . That is, using both extruder-type melt extruder for both polymers,
As a fiber cross section, the core-sheath composite fiber was melt-spun through a core-sheath type spinneret having a polyethylene polymer sheath and a polyethylene terephthalate polymer core. At the time of melt spinning, the melting temperature of the polyethylene polymer was 230 ° C., the melting temperature of the polyethylene terephthalate polymer was 285 ° C., the single-hole discharge rate was 1.27 g / min, and the composite ratio of the polyethylene polymer and the polyethylene terephthalate polymer was 1 / 1
Under the following conditions. After cooling the melt-spun yarn with a known cooler, the yarn is drawn using an air sucker at a drawing speed of 3800 m / min, opened using a known opening device, and collected on a moving collecting surface. -It was made to be a long fiber web A2. Single yarn fineness is 3.3 dtex,
The basis weight was 100 g / m ² .

On the other hand, using the same polyethylene polymer and polyethylene terephthalate polymer applied to the long fiber web A2, a split composite long fiber nonwoven fabric B was produced by a spun bond method. That is, the fiber cross section of each of the above-mentioned polymers was measured using an individual extruder-type melt extruder.
The split split composite fiber was melt-spun through a spinneret having a sectional shape as shown in FIG. At the time of melt spinning, the melting temperature of the polyethylene polymer was set to 230 ° C., the melting temperature of the polyethylene terephthalate polymer was set to 285 ° C., and the single hole discharge amount =
The melt composite spinning was carried out under the condition that the polyethylene polymer was disposed in the core and the polyethylene terephthalate polymer was disposed in 6 segments at a composite ratio of 1.1 at 1.2 g / min. After cooling the melt-spun yarn with a known cooler, the yarn is drawn using air soccer at a drawing speed of 3600 m / min, opened using a known opening device, and collected on a moving collecting surface. -It was made to be a split composite long fiber web. Single yarn fineness is 3.3
Decitex (polyethylene: 1.65 decitex,
Polyethylene terephthalate: 0.275 dtex x 6), and the basis weight was 120 g / m ² .

Next, the products are collected on the collecting surface for moving both webs.
After layering (the long fiber web A2 is on the collection surface side, split fiber composite long fiber
The web was layered on top of it. ), Embossed
And heat-welded to both webs.
220g / m per unit weight ^TwoOf composite long-fiber nonwoven fabric
Was. The condition of the hot pressing process is that the area is 0.6mm^TwoDiamond shape
Sculpture pattern has a pressure contact density of 20 points / cm^Two, Pressed area ratio 1
2% embossing roll and metal with smooth surface
Rolls were used. This embossing roll and the surface is smooth
The surface temperature of the metal roll is 125 ° C and the line between both rolls
The pressure was 500 N / cm.

Next, the composite long-fiber nonwoven fabric was placed on a 50-mesh wire mesh and subjected to a high-pressure liquid flow treatment from the split composite long-fiber nonwoven fabric B side. The high pressure liquid flow treatment has a pore size of 0.12
50 mm above the laminate using a high-pressure liquid flow treatment device in which the injection holes each having a diameter of 0.62 mm are arranged in a three-group arrangement at an interval of 0.62 mm.
The high-pressure liquid flow was applied in two stages from the position. First, the treatment was performed once at a water pressure of 4.4 MPa, and subsequently, three times at a water pressure of 6.9 MPa. By this high-pressure liquid flow treatment, in the cross-section of the split-type composite fiber constituting the split-type composite long-fiber nonwoven fabric B, splitting was performed at the boundary surface of the constituent polymers, and ultrafine splitting fibers were developed. After the high-pressure liquid treatment, excess moisture is removed from the composite nonwoven fabric and a drying treatment is performed.
0 g / m ² of the composite long-fiber nonwoven fabric of the present invention was obtained.

Example 2 In Example 1, a long-fiber nonwoven fabric A having a basis weight of 100 g / m ² consisting of only a polyethylene polymer without using a polyethylene terephthalate polymer was used instead of the long-fiber nonwoven fabric A2.
1, and the basis weight of the split composite long-fiber nonwoven fabric B was 10
Except having set it as 0 g / m < ² >, it carried out similarly to Example 1, and obtained the composite continuous fiber nonwoven fabric of this invention of 200 g / m < ² >.

Example 3 In Example 1, the basis weight of the long-fiber nonwoven fabric A2 was 200 g.
/ M ² , the same as Example 1, except that the split fibers of the constituent fibers of the split composite long-fiber nonwoven fabric B had a cross-sectional shape of 30 as shown in FIG. Thus, a composite long-fiber nonwoven fabric of the present invention having a basis weight of 320 g / m ² was obtained.

Comparative Example 1 Using a polyethylene terephthalate polymer chip having the same melting point of 255 ° C. and a relative viscosity of 1.38 as in Example 1, a long fiber nonwoven web made of polyethylene terephthalate by a spun bond method was produced. That is, the polymer chip is melted and melted and spun through a round spinning hole at a spinning temperature of 285 ° C. and a single hole discharge rate of 1.3 g / min. After cooling at, take off at a traction speed of 4000 m / min using air soccer,
The web was opened using a known opening device, collected and deposited on a moving collecting surface to form a web. The single fiber fineness was 3.3 dtex. Next, the web was subjected to a heat-pressure treatment to obtain a long-fiber nonwoven fabric with a basis weight of 200 g / m ² . The conditions of the heat pressing treatment are as follows: an embossing roll in which a diamond-shaped engraved pattern having an area of 0.6 mm ² is disposed at a pressing contact density of 20 points / cm ² and a pressing contact area ratio of 12%, and a metal roll having a smooth surface. Using. The surface temperature of the embossing roll and the metal roll having a smooth surface is 230 ° C., and the linear pressure between the two rolls is 500
N / cm.

Comparative Example 2 In Example 1, the basis weight of the long-fiber nonwoven fabric A2 was 100 g.
/ M ² , the basis weight of the split composite long-fiber nonwoven fabric B is 120 g / m ²
A nonwoven fabric with a basis weight of 220 g / m ² was obtained in the same manner as in Example 1 except that the high-pressure liquid flow treatment after the heat-pressure welding treatment was not performed.

Comparative Example 3 The same procedure as in Example 1 was carried out except that the nonwoven fabric A2 was not used and the basis weight of the split nonwoven fabric B was 200 g / m ² . A high-pressure liquid flow treatment was performed to obtain a long-fiber nonwoven fabric having a basis weight of 200 g / m ² .

The physical properties of the composite long-fiber nonwoven fabrics of Examples 1 to 3 and Comparative Examples 1 to 3 were measured and are shown in Table 1.

[0055]

[Table 1]

As can be seen from the results in Table 1, Examples 1 to
The composite long-fiber nonwoven fabric obtained in No. 3 was excellent in dust collecting property (collecting efficiency), high in compression stiffness and excellent in pleating workability, and thus was suitable as an air filter.

On the other hand, the composite long-fiber nonwoven fabrics obtained in Comparative Examples 1 and 2 have a low value of the collection efficiency and are inferior in the dust collection property,
It could not be used for filter applications, and was not the object of the present invention. The long-fiber nonwoven fabric obtained in Comparative Example 3 is excellent in dust collection efficiency but is too flexible,
It was inferior in pleating workability and was not the object of the present invention.

[0058]

According to the present invention, one surface is made of a long-fiber nonwoven fabric having a low-melting polymer, and one surface is made of a long-fiber nonwoven fabric containing microfibers. Glued. Therefore, the long-fiber nonwoven fabric side including the ultrafine fibers has flexibility, and has a small inter-fiber space, so that it is excellent in dust collection. On the other hand, on the side of the long-fiber nonwoven fabric having a low-melting-point polymer, the low-melting-point polymer is resinified by softening or melting, and thus has an appropriate rigidity.

The filter comprising the nonwoven fabric of the present invention has a large interfiber space and high rigidity on the long fiber nonwoven fabric side having a low melting point polymer as compared with the long fiber nonwoven fabric containing ultrafine fibers. , And relatively large dust can be collected in advance. Further, after collecting large dust in advance, fine dust can be collected on the nonwoven fabric side made of ultrafine fibers having a small inter-fiber gap, and clogging hardly occurs in the nonwoven fabric made of ultrafine fibers, and the dust is not collected for a long time. It becomes a usable filter. In addition, since the low-melting-point polymer is converted into a resin and the two nonwoven fabrics are bonded and integrated, the pleated workability of the composite nonwoven fabric is good.

The filter made of the nonwoven fabric of composite long fiber of the present invention is not only an air filter installed in an air cleaner or a vacuum cleaner, but also a filter cloth for food industry, a filter cloth for removing particles from well water and the like, and a filter cloth for iron removal. It can also be suitably used for applications.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a cross-sectional shape of a splittable conjugate long fiber used in the present invention.

FIG. 2 is a schematic view showing another example of the cross-sectional shape of the splittable conjugate long fiber used in the present invention.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yasuhiro Yonezawa 4-1 Hina Kitamachi, Okazaki City, Aichi Prefecture Unitika Ltd. Okazaki Plant F-term (reference) 4D019 AA01 AA03 BA13 BB03 BB10 BD10 CB06 DA02 DA06 4F100 AK01A AK04A AK04B AK42A AK42B BA02 BA16 DG04A DG04B DG15A DG15B DG18B DG20A DG20B EC03 EJ40 GB56 JA04A JK13 JK17 4L047 AA14 AA21 AA23 AA27 AB03 AB08 BA09 BB01 CA05 CC12

Claims (5)

[Claims] 1. A long-fiber nonwoven fabric A1 comprising a low-melting polymer
And a long-fiber nonwoven fabric B containing ultrafine fibers, which are laminated and heat-bonded by melting or softening of the low-melting-point polymer. 2. A long-fiber nonwoven fabric A2 composed of a low-melting-point polymer and a high-melting-point polymer and a long-fiber nonwoven fabric B containing ultrafine fibers are laminated and thermally bonded by melting or softening of the low-melting-point polymer. A composite long-fiber nonwoven fabric, characterized in that: 3. The long-fiber nonwoven fabric B contains an ultrafine fiber obtained by splitting a splittable conjugate fiber made of two types of polymers having incompatibility with each other. The composite long-fiber nonwoven fabric according to the above. 4. The long-fiber nonwoven fabric A2 is made of a core-in-sheath composite fiber in which a high-melting polymer is disposed in a core portion and a low-melting polymer is disposed in a sheath portion. 4. The composite long-fiber nonwoven fabric according to 3. 5. A filter comprising the composite long-fiber nonwoven fabric according to any one of claims 1 to 4.