JP2008190051A - High-efficiency nonwoven fabric with low pressure loss - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency nonwoven fabric with a low pressure loss sufficiently reinforced with little reinforcing processing when assembled in a filter unit and having a small load and a long filter life without using a melt-blown nonwoven fabric. <P>SOLUTION: The nonwoven fabric is obtained by forming a staple fiber layer composed of heat adhesive conjugated staple fibers into a dense layer part and forming a staple fiber layer composed of mixed fibers of thermoplastic staple fibers with heat adhesive conjugated staple fibers into a coarse layer part, laminating both the staple fiber layers and integrating the resultant laminate. The nonwoven fabric has a stiffness strength of 2.5-9.0 N and a 1 mm compression deformation stress of 1.5-7.0 N/cm<SP>2</SP>/mm. Preferably, the weight mass of the laminated and integrated nonwoven fabric is within the range of 100-250 g/m<SP>2</SP>, the thickness is within the range of 1.0-4.0 mm, and the mixed fiber range of both the staple fibers in the coarse layer part is within the range of (10/90) to (40/60). The weight mass ratio of the coarse layer to the dense layer of the nonwoven fabric is preferably within the range of (25/75) to (50/50). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-woven fabric for a filter, and more particularly to a low-pressure loss high efficiency filter non-woven fabric.

Recently, in addition to air pollution in urban areas, there has been a growing demand for pollen-compatible non-woven fabrics as cabin filters, and various studies have been made, and melt blown non-woven fabrics and those obtained by subjecting non-woven fabrics to electret treatment have been taken up. (For example, see Patent Documents 1 and 2)
Among these, melt blown nonwoven fabric is the most common, but has good performance but relatively high initial pressure loss and a short filter life. In addition, when the pleats are incorporated into the filter unit, the heel contact is likely to occur, and it is necessary to reinforce the heel fixing to prevent the heel contact. This is thought to be due to the low waist strength of the nonwoven fabric, and there is a problem that the cost is high.

On the other hand, a low-cost medium-performance filter as a low-pressure loss nonwoven fabric has low filter performance and low waist strength. In order to achieve high efficiency, it is sufficient to simply increase the amount of fibers (weight per unit area), but conversely, the initial pressure loss increases, and the thickness also increases, and it is difficult to limit the width of the pleating pitch. .
JP-A-10-148200 JP 2003-236319 A

  In view of the actual situation as described above, the present invention requires less reinforcement when incorporated in a filter unit, has a low load, has a long filter life, i.e., low pressure loss and high efficiency, and has high waist strength. It is an object of the present invention to provide a nonwoven fabric having a low pressure loss, high efficiency and high waist strength without using a melt blown nonwoven fabric.

  As a method for obtaining a low pressure loss without using a melt blown nonwoven fabric, it is conceivable to first improve the current filter for coarse dust. Some coarse dust filters are made of a mixture of thermoplastic short fibers and heat-adhesive composite short fibers, but have low filtration performance and low waist strength. Therefore, the present inventor has made various studies on blending of thermoplastic short fibers and heat-adhesive composite short fibers, and as a result, found that the heat-adhesive composite short fiber layer is combined as a dense layer, and reached the present invention. .

That is, the present invention suitable for the above-mentioned object is a short fiber composed of a mixture of a thermoplastic short fiber and a heat-adhesive composite short fiber. A nonwoven fabric obtained by laminating and integrating both short fiber layers with a layer as a coarse layer portion. The nonwoven fabric has a waist strength of 2.5 N to 9.0 N, and a 1 mm compressive deformation stress of 1.5 N / cm ² / mm to 7 It is a nonwoven fabric which is 0.0 N / cm ² / mm.

Here, both short fiber layer of the coarse layer and dense layer are integrated nonwoven fabric, its weight per unit area mass is ^{100g / m 2 ~250g / m 2} , the thickness is 1.0mm~4.0mm It is preferable. Further, the mixing ratio of the thermoplastic short fibers and the thermoadhesive composite short fibers in the coarse layer portion is preferably in the range of 10/90 to 40/60. It is effective that the basis weight ratio is in the range of 25/75 to 50/50. In addition, the heat-adhesive conjugate fiber to be used is a fiber having a sheath core structure, and a sheath portion having a melting point lower than that of the core portion and having a range of 100 ° C. to 180 ° C. is preferable.

Thus, finally, the nonwoven fabric of the present invention is a mixture of a dense layer composed of a heat-adhesive composite short fiber layer and a thermoplastic short fiber and a heat-adhesive short fiber, and the fiber mixture ratio is 10/90 to 40/60. a nonwoven fabric was allowed piece laminate and a rough layer portion made of a short fiber layer is, the thickness of the nonwoven fabric 1.0-4.0 mm, weight per unit area mass with ^{100g / m 2 ~250g / m 2} , and The mass ratio of the coarse layer portion and the dense layer portion is 25/75 to 50/50, and the nonwoven fabric has a waist strength of 2.5 N to 9.0 N, 1 mm compressive deformation stress of 1.5 N / cm ² / mm to Features a nonwoven fabric in the range of 7.0 N / cm ² / mm.

  The non-woven fabric of the present invention can maintain a proper air permeability by the heat-bonding composite short fibers in the dense layer portion and improve the waist strength, and is good by mixing the thermoplastic short fibers and the heat-bonding composite short fibers. Bulkiness can be obtained, and a good filtration performance can be maintained by the total of these. Also, by setting the waist strength and 1mm compressive deformation stress of the nonwoven fabric within the predetermined ranges, the filter has good moldability, the wrinkle contact in the unit after pleating is suppressed, and the reinforcing processing for preventing wrinkle contact is reduced. The filtration performance is also improved.

  Hereinafter, specific embodiments of the present invention will be described in detail.

As described above, the nonwoven fabric of the present invention has a dense layer portion composed of a heat-adhesive composite short fiber layer, and a coarse layer portion composed of a short fiber layer composed of a mixture of thermoplastic short fibers and heat-adhesive composite short fibers. a nonwoven fabric layers are laminated and integrated, waist strength of the nonwoven fabric is 2.5N～9.0N, 1 mm compressive deformation stress of 1.5N / cm ² /mm~7.0N/cm ² / mm By being in the range, the moldability of the filter is good, the wrinkle contact in the unit after the pleating process is suppressed, the reinforcing process for preventing wrinkle contact is reduced, and the filtration performance is improved.

  That is, the nonwoven fabric of the present invention is first constituted by laminating and integrating a dense layer portion from a thermoadhesive conjugate fiber and a coarse layer portion composed of a mixture of thermoplastic short fibers and a thermoadhesive conjugate fiber. As the heat-adhesive composite short fibers constituting the dense layer portion, the fineness is preferably in the range of 3.0 to 30.0 decitex (dtex) and the average fineness is in the range of 3.0 to 10.0 decitex, and the dense layer portion is applied. It is composed only of heat-bondable composite short fibers. If the average fineness is less than 3.0 decitex, it is not preferable because the fineness is too thin and it is difficult to obtain a desired air permeability by heat fusion with the heat-adhesive composite short fiber.

  On the other hand, if the fineness of the heat-adhesive composite short fiber exceeds 30.0 decitex, the ventilation becomes rough, and it is not preferable because fine air permeability is difficult to set. The combination of fineness is 3.0 to 10 in average fineness. The range of 0.0 decitex is good and a desired air permeability can be obtained.

  In addition, the short fibers constituting the coarse layer portion have a role in the fiber layer because the role of the thermoplastic short fibers does not have an adhesive ability, and the role of the heat-adhesive composite short fibers is between the fibers. Acts as a glue. The fineness of the thermoplastic short fiber in the coarse layer portion is effectively in the range of 5.0 to 10.0 decitex, and if the fineness is less than 5.0 decitex, it becomes thin and has no waist and bulk. It is not preferable. On the contrary, if the fineness exceeds 10.0 dtex, it becomes too coarse, which is not preferable.

  On the other hand, the fineness of the heat-adhesive conjugate fiber is preferably in the range of 3.0 to 30.0 dtex. If the fineness is less than 3.0 decitex, it is not preferable that the adhesion becomes dense and causes no loose bulk. Conversely, if the fineness exceeds 30.0 decitex, the adhesion becomes too coarse, which is not preferable. . In addition, the blend ratio of the thermoplastic short fiber and the thermoadhesive composite short fiber in the coarse layer portion is preferably in the range of 10/90 to 40/60 from the point of bulkiness, and the thermoplastic short fiber is less than 10 If it exists, the bulky effect is not obtained, which is not preferable. On the other hand, if the number of thermoplastic short fibers exceeds 40, there is a bulky effect, but it is difficult to control the adhesion between the fibers and it is difficult to obtain an appropriate bulkiness. And although the said short fiber layer is laminated | stacked and integrated in this invention nonwoven fabric, the fabric weight ratio of the rough | crude layer and dense layer of the nonwoven fabric which the short fiber layer laminated | stacked and integrated is 30 / 70-50 ~. A range of 50 is preferred. If the mass ratio of the coarse layer is less than 30, the effect of the coarse layer is lost, and the filtration performance is deteriorated by showing the behavior of the dense layer. On the other hand, if the mass per unit area of the coarse layer exceeds 50, the effect of the dense layer cannot be exhibited.

The nonwoven short fiber layer are integrated by stacking is preferably in a range basis weight mass of ^{100g / m 2 ~250g / m 2} , and the thickness is preferably in the range of 1.0mm~4.0mm . If the weight per unit area is less than 100 g / m ² , the effect of the coarse layer and the dense layer is lost. On the other hand, when the mass per unit area exceeds 250 g / m ² , it is difficult to reduce the thickness and it is difficult to obtain an appropriate thickness. Since the thickness is less than 1.0mm, the pitch of the pleats can be made fine when processed by pleating, but it is difficult to have a moderate waist. Therefore, it is not preferable, and if the thickness exceeds 4.0 mm, the pitch cannot be reduced by pleating. As a result, when processed into a product, there is a difficulty that the filtration area cannot be increased.

  Here, as the heat-adhesive conjugate fiber used for the dense layer portion and the coarse layer portion, a sheath core structure having a high melting point component as a core and a low melting point component as a sheath is good, and a side-by-side structure is compared with a core-sheath structure. However, only half the adhesion point can be obtained.

  The melting point of the low melting point component is lower than that of the high melting point component and is preferably in the range of 100 ° C. to 180 ° C., and less than 100 ° C. is not preferable from the viewpoint of heat resistance of the filter. On the other hand, if the temperature exceeds 180 ° C., the adhesion between the short fibers is poor, and if the temperature is increased for adhesion, the damage to the thermoplastic fibers increases, which is not preferable. In particular, the coarse layer portion is not preferably 100% heat-adhesive fiber because the core of the bonding intersection is lost. However, in the dense layer portion, 100% heat-adhesive conjugate fiber is used, so that the moldability by heat pleating can be improved. Good due to the presence of low melting point components.

  In addition, as the heat-adhesive conjugate fiber, fibers made of a composite of a high melting point component such as nylon and polyester and a low melting point component can be used, but practically a composite having a high melting point polyester as a core and a low melting point polyester as a sheath. Fiber is used.

  The present invention is based on the filter nonwoven fabric obtained by laminating and integrating the dense layer portion and the coarse layer portion as described above. However, in order to obtain the desired low pressure loss high efficiency effect, the nonwoven fabric further has the following waist strength and 1 mm compression. It is important to have deformation stress.

  First, it is important for the waist strength that the numerical value obtained by the following method is in the range of 2.5N to 7.0N. That is, a rectangular sample having a length of 80 mm and a width of 65 mm was cut out, folded into a half (40 mm) uniformly from the center of the length with the dense layer surface facing, the sample was placed on the sample setting table, A compression jig (10 mmφ) is applied to the apex center of the peak with a V-shaped width of 40 mm at the bottom. Then, using a 100 Kg Tensilon manufactured by Toyo Bald-In Co., Ltd., the compression measurement is set to n = 5 with a 100 mmφ compression jig, the average value thereof, and the unit is expressed in terms of N.

  If the waist strength obtained as described above is less than 2.5N, the nonwoven fabric is soft, pleated and incorporated into the filter unit, so that it is easy to come into contact with the heel, which requires several heel fixings, which is not preferable. Moreover, when the waist strength by the above exceeds 9.0N, it is good from the point of heel contact, but the ventilation | gas_flow amount which passes a filter reduces and passage resistance becomes high.

On the other hand, another 1mm compressive deformation stress, it is effective values calculated by the following is 1.5N / cm ² /mm~7.0N/cm ² / mm range. This 1 mm compressive deformation stress mainly indicates the compressive deformation stress of the coarse layer part. The low deformation stress indicates that the filter is easily deformed and the filtration performance after pleating is reduced. On the other hand, if it is high, the effect of the coarse layer portion is lost. It is possible to secure the 1.5 N / cm ² aeration of /mm~7.0N/cm ² / mm filament cabin filters, etc. The range of ^{200cc / cm 2 / sec~600cc / cm} 2 / sec . In addition, 1 mm compressive deformation stress is calculated | required by the compression test as follows.

That is, using a Toyo Bald-In 100 kg Tensilon, the sample was compressed at a compression area of 2 cmφ and a compression speed of 5 mm / min, and an initial load of 0.02 kg / cm ² was deformed to obtain a stress of 1 mm. The unit is stress per unit area, and is expressed in terms of N. In addition, a measurement is set to n = 5 and shows the average value.

  Examples of the present invention are shown below together with comparative examples.

Example 1
10% by weight polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 54 mm (melting point of the low melting polyester: 110 ° C.) A coarse layer fiber web having a basis weight of 65 g / m ² comprising 10% by weight and 80% by weight of a polyester / low-melting polyester composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm (melting point of low-melting polyester: 110 ° C.). And 100% by weight of polyester / low-melting polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of low-melting polyester: 110 ° C.), and a dense layer fiber having a basis weight of 100 g / m ² , denser layer side, depth 18 mm, subjected to a needle punching treatment at end counts forty / cm ^2, 1 Heat-treated for 40 seconds with a 5 ° C pin tenter heat treatment machine, contacting the dense layer surface with a hot roll with a surface temperature of 110 ° C, calendering with a clearance of 0.5 mm between both rolls treated on both sides, cooling and low pressure loss A highly efficient nonwoven fabric was obtained. The obtained nonwoven fabric had an actual weight per unit area of 167 g / m ² and a thickness of 2.2 mm.

Example 2
Polyester fiber with a fineness of 6.0 dtex and a fiber length of 51 mm (melting point: 260 ° C.) 10% by weight, and a polyester / low melting point polyester composite fiber with a fineness of 4.4 dtex and a fiber length of 54 mm (melting point of the low melting point polyester: 110 ° C.) Laminating 10% by weight, dense layer fiber having a fineness of 16.7 dtex and a fiber length of 64 mm and a polyester / low melting point polyester composite fiber (melting point of low melting point polyester: 100 ° C.) of 100% by weight and a basis weight of 100 g / m ² Then, from the dense layer side, needle punching is performed at a depth of 12 mm and the number of driven wires is 40 / cm ² , and heat-treated for 40 seconds with a 165 ° C. pin tenter heat treatment machine, and the dense layer surface is heated to a hot roll having a surface temperature of 110 ° C. The contact between both sides of the rolls, both sides treated with a clearance of 0.5mm, calendered, cooled and low pressure loss high An efficient nonwoven fabric was obtained. The obtained nonwoven fabric had an actual weight per unit area of 119.9 g / m ² and a thickness of 2.3 mm.

Example 3
10% by weight polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 54 mm (melting point of the low melting polyester: 110 ° C.) A coarse layer fiber web having a basis weight of 45 g / m ² consisting of 80% by weight, a polyester / low melting point polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of low melting point polyester: 110 ° C.) 70% by weight And a dense layer fiber having a basis weight of 100 g / m ² and a polyester / low melting point polyester composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm (melting point of low melting point polyester: 110 ° C.) 30% by weight. , from dense layer side, depth 12 mm, subjected to a needle punching treatment at end counts forty / cm ^2, Heat treated for 40 seconds with a 65 ° C pin tenter heat treatment machine, the dense layer surface was brought into contact with a hot roll with a surface temperature of 110 ° C, the clearance between both rolls treated on both sides was calendered to 0.5 mm, cooled and low pressure loss A highly efficient nonwoven fabric was obtained. The obtained nonwoven fabric had an actual weight per unit area of 149.0 g / m ² and a thickness of 3.3 mm.

Example 4
10% by weight polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 54 mm (melting point of the low melting polyester: 110 ° C.) A coarse layer fiber web having a basis weight of 65 g / m ² , comprising 10% by weight and 80% by weight of a polyester / low-melting polyester composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm (melting point of low-melting polyester: 110 ° C.) 70% by weight of polyester / low-melting polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of low-melting polyester: 100 ° C.), and a polyester / low melting point / composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm ( (Melting point of low melting point polyester 110 ° C.) 30% by weight After laminating a dense layer for fiber 5 g / m ^2, from the dense layer side, depth 12 mm, subjected to a needle punching treatment at end counts forty / cm ^2, and heat-treated for 40 seconds at 165 ° C. in a pin tenter type heat treatment apparatus The dense layer surface was brought into contact with a hot roll having a surface temperature of 110 ° C., the clearance between both rolls treated on both sides was calendered to 0.5 mm, and cooled to obtain a low-pressure loss high-efficiency nonwoven fabric. The obtained nonwoven fabric had an actual weight per unit area of 196.0 g / m ² and a thickness of 3.8 mm.

Comparative Example 1
10% by weight of a polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low-melting polyester composite fiber having a fineness of 16.7 decitex and a fiber length of 64 mm (melting point of the low-melting polyester: 110 ° C.) A web having a basis weight of 110 g / m ² consisting of 90% by weight is subjected to needle punching at a depth of 10 mm and a driving number of 40 / cm ² , and heat treated for 40 seconds with a pin-tenter heat treatment machine at 165 ° C. Was contacted with a hot roll at 110 ° C. and the clearance between both side rolls treated on both sides was calendered to 0.5 mm to obtain a nonwoven fabric. The obtained nonwoven fabric had a weight per unit area of 110 g / m ² and a thickness of 3.0 mm.

Comparative Example 2
A melt blown nonwoven fabric (average fiber diameter: 1.6 μmφ) made of polypropylene resin and a basis weight of 20 g / m ² and a spunbond nonwoven fabric of polyester resin (average fiber diameter: 25.0 μmφ) are 50 g / m ² and are bonded together. A nonwoven fabric having a mass of 125 g / m ² and a thickness of 0.7 mm was obtained.

Comparative Example 3
10% by weight polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 54 mm (melting point of the low melting polyester: 110 ° C.) A coarse layer fiber web having a basis weight of 65 g / m ² comprising 10% by weight and 80% by weight of a polyester / low-melting polyester composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm (melting point of low-melting polyester: 110 ° C.). 30% by weight of a polyester fiber (melting point: 260 ° C.) having a fineness of 1.3 dtex and a fiber length of 51 mm, and a polyester / low-melting polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of the low-melting polyester: 110) ° C) 70% by weight, and a dense layer fiber having a mass per unit area of 100 g / m ² was laminated. After that, from the dense layer side, needle punching is performed at a depth of 12 mm and the number of driven wires is 40 / cm ² , and heat treated for 40 seconds with a 165 ° C. pin tenter heat treatment machine, and the dense layer surface is heated to a hot roll having a surface temperature of 110 ° C. The clearance between both rolls that were brought into contact with each other and treated on both sides was calendered to 0.5 mm to obtain a nonwoven fabric. The obtained nonwoven fabric had a basis weight of 165 g / m ² and a thickness of 3.2 mm.

Comparative Example 4
10% by weight polyester fiber (melting point: 260 ° C.) having a fineness of 6.6 decitex and a fiber length of 51 mm, and a polyester / low melting point polyester composite fiber having a fineness of 4.4 decitex and a fiber length of 54 mm (melting point of the low melting polyester: 110 ° C.) A coarse layer fiber web having a weight per unit area of 110 g / m ² consisting of 10% by weight and 80% by weight of polyester / low-melting polyester composite fiber having a fineness of 16.7 dtex and a fiber length of 64 mm (melting point of low-melting polyester: 110 ° C.). And a polyester / low-melting polyester composite fiber having a fineness of 4.4 dtex and a fiber length of 51 mm (melting point of low-melting polyester: 110 ° C.) at 100% by weight and a dense layer fiber having a basis weight of 160 g / m ² , denser layer side, depth 10 mm, subjected to a needle punching treatment at end counts forty / cm ^2, 1 Treated with a pin tenter type heat treatment machine at 5 ° C for 40 seconds, bringing the dense layer surface into contact with a hot roll with a surface temperature of 110 ° C, and calendering the clearance between both rolls treated on both sides to 0.5 mm to obtain a nonwoven fabric It was. The nonwoven fabric was subjected to needle punching at a depth of 5 mm and a driving number of 105 pieces / cm ² from the dense layer portion toward the coarse layer portion. The obtained nonwoven fabric had an actual weight per unit area of 270 g / m ² and a thickness. Was 4.6 mm.

  About each nonwoven fabric obtained by the above each Example and comparative example, the performance and product evaluation were contrasted. The results are shown in Table 1.

なお、上記表中における目付量，厚さ，通気度の測定ならびに各評価は下記に従った。また、腰強度，１ｍｍ圧縮変形応力は前述した方法により夫々算出した。
（イ）目付量：ｇ／ｍ²
５０ｃｍ×５０ｃｍの大きさを切り出し、その時の重さを測定し、１ｍ²当たりの重量に換算した。
（ロ）厚さ：ｍｍ
１５ｃｍ×１５ｃｍの大きさを切り出し、初荷重１５ｇ／ｃｍ²をかけて、４隅の高さを測定し、その平均値で示した。
（ハ）通気度
ＪＩＳ Ｌ １０９６−１９９９の８２７．１のＡ法により測定した。
（ニ）濾過性能の評価
塵埃捕集性能の試験はＪＩＳ Ｄ１６１２の自動車用エアクリーナー試験法に基づいて行なった。但し、試験用のエアークリーナーのエレメントは有効面積１０００ｃｍ²の円板濾材を使用した。実験条件は、濾材通過見掛け風量を４０ｃｍ／ｓｅｃとし、ＪＩＳ Ｚ ８９０１で指定の８種粉体の塵埃濃度は１ｇ／ｍ³とし、濾過面積１０００ｃｍ²に対し清浄効率は増加抵抗３００ｍｍＡｑ時における捕集効率とした。
評価項目
通気抵抗 （ΔＰ）
清浄効率 （η）
塵埃保持量 （ＤＨＣ）
実験条件
ＪＩＳ８種塵埃（ＪＩＳ Ｚ８９０１）塵埃濃度は１ｇ／ｍ³
試験用のエアークリーナーのエレメント 有効面積１０００ｃｍ³の円板濾材
試験風速 ４０ｃｍ／ｓｅｃ
ΔＰ ：試料セット前後の初期圧力差
η ：増加抵抗３００ｍｍＡｑ時における塵埃捕集効率
ＤＨＣ：増加抵抗３００ｍｍＡｑ時における塵埃保持量
（ホ）製品評価
（ａ）試料の調整：試料は巾２１０ｍｍで山と山の頂点間の距離が１０ｍｍ、谷と谷の頂点間の距離が１０ｍｍで、山と谷の距離が３０ｍｍのプリーツ加工をし、山数を１５として両側を不織布に接着（クロロプレンゴム：コニシ株式会社製「ボンドＧ１７」）して固定した。
（ｂ）プリーツピッチ１０ｍｍ以下評価：試料調整した製品の襞の接触状態を評価した。

The measurement of the basis weight, thickness, and air permeability and the evaluations in the above table were as follows. The waist strength and 1 mm compressive deformation stress were calculated by the methods described above.
(A) Weight per unit area: g / m ²
A size of 50 cm × 50 cm was cut out, the weight at that time was measured, and converted to a weight per 1 m ² .
(B) Thickness: mm
A size of 15 cm × 15 cm was cut out, an initial load of 15 g / cm ² was applied, the heights of the four corners were measured, and the average value was shown.
(C) Air permeability Measured by the method A of 827.1 of JIS L 1096-1999.
(D) Evaluation of filtration performance The dust collection performance test was conducted based on the automotive air cleaner test method of JIS D1612. However, a disk filter medium having an effective area of 1000 cm ² was used as an element of the test air cleaner. The experimental conditions are that the apparent air flow rate through the filter medium is 40 cm / sec, the dust concentration of the eight kinds of powders specified in JIS Z 8901 is 1 g / m ^3, and the cleaning efficiency is increased at a resistance of 300 mmAq for a filtration area of 1000 cm ^2. The efficiency.
Evaluation item Ventilation resistance (ΔP)
Clean efficiency (η)
Dust retention (DHC)
Experimental conditions JIS class 8 dust (JIS Z8901) dust concentration is 1 g / m ³
Air cleaner element for testing Disc filter medium with effective area of 1000 cm ³ Test wind speed 40 cm / sec
ΔP: Initial pressure difference before and after sample setting η: Dust collection efficiency when increasing resistance is 300 mmAq DHC: Dust retention amount when increasing resistance is 300 mmAq (e) Product evaluation (a) Sample adjustment: Sample is 210 mm wide The distance between the vertices is 10mm, the distance between the vertices of the valley and the valley is 10mm, and the distance between the peaks and valleys is 30mm. The number of peaks is 15, and both sides are bonded to the nonwoven fabric (chloroprene rubber: Konishi "Bond G17" manufactured) and fixed.
(B) Pleated pitch of 10 mm or less Evaluation: The contact state of the ridges of the prepared products was evaluated.

襞 15 does not touch all ○
The range of 1-5 is contacting in 襞 15.
6 or more of 襞 15 are in contact ×
(C) Reinforcement of pleats 2 points or less: Evaluation of the bending state of the wrinkles of the prepared product.

It is good to fix with reinforcement of up to 2 points with little bending of the heel.
Reinforcement is required by fixing 3 points with little warpage
Reinforcement is required by fixing 4 points or more with little warp deflection ×
(D) Shape retention evaluation: The state of the product prepared after heat treatment was evaluated.

  Treatment state: A pleated unit was set so that hot air hits the coarse layer part, and the discharge air speed was adjusted by the exhaust duct of the temperature controller.

Evaluation device: Digital temperature indicating controller PMS-B manufactured by Tabai Espec
Temperature: 80 ° C
Wind speed: 30.0m / sec
Processing time: 5.0 hour evaluation The state of mountain, valley and valley does not change at all and there is no wrinkle contact ○
Some of the mountains and valleys are slightly uneven, with slight wrinkles △
Mountains and valleys are greatly deformed and wrinkled
From Table 1 above, the nonwoven fabrics of the present invention all have low pressure loss and generally good cleaning efficiency as compared with the comparative example, the filter moldability is good in product evaluation, and the wrinkles in the unit after pleating It can be seen that the contact is suppressed, and the shape retention is excellent as well as the reduction of the reinforcing process for preventing wrinkle contact.

Claims (6)

The short fiber layer composed of heat-bondable composite short fibers is used as a dense layer part, and the short fiber layer composed of a mixture of thermoplastic short fibers and heat-adhesive composite short fibers is used as a coarse layer part. a allowed nonwoven, a waist strength 2.5N～9.0N, and is 1mm compressive deformation stress being a 1.5N / cm ² /mm~7.0N/cm ² / mm Low pressure loss high efficiency nonwoven fabric. The mass per unit area of the nonwoven fabric in which both the coarse and dense short fiber layers are laminated and integrated is 100 g / m ^{2 to} 250 g / m ² , and the thickness is in the range of 1.0 mm to 4.0 mm. The low-pressure loss high-efficiency nonwoven fabric described.   The low-pressure-loss high-efficiency nonwoven fabric according to claim 1 or 2, wherein the mixing ratio of the thermoplastic short fibers in the coarse layer portion and the heat-adhesive composite short fibers is in the range of 10/90 to 40/60.   The low-pressure-loss high-efficiency nonwoven fabric according to claim 1, 2 or 3, wherein the mass ratio of the coarse layer and the dense layer of the laminated nonwoven fabric is in the range of 25/75 to 50/50.   The low-pressure loss high-efficiency nonwoven fabric according to any one of claims 1 to 4, wherein the heat-adhesive conjugate fiber is a fiber having a sheath-core structure, and the melting point of the sheath is in the range of 100 ° C to 180 ° C. A dense layer portion composed of a heat-adhesive composite short fiber layer and a coarse layer composed of a short fiber layer composed of a mixture of thermoplastic short fibers and heat-adhesive short fibers, the mixing ratio of which is 10/90 to 40/60 part a nonwoven fabric was allowed integrally laminated, thickness 1.0-4.0 mm, with a basis weight mass ^{100g / m 2 ~250g / m 2} , and the basis weight weight ratio of Araso portion and the dense layer portion with a 25/75 to 50/50, and wherein the waist strength 2.5N～9.0N, 1 mm compressive deformation stress is 1.5N / cm ² /mm~7.0N/cm ² / mm Low pressure loss high efficiency nonwoven fabric.