Filter reinforcing material and filter medium for deodorizing filter comprising same

Abstract

A filter reinforcing material is disclosed that does not cause peeling or pleat adhesion at the time of pleating, is excellent in pleating, and has high stiffness. A filter reinforcing material includes a bonding layer comprising a thermal bonded nonwoven including thermal bondable short fibers, and a reinforcing layer comprising a nonwoven including high-melting fibers having a higher melting point than a melting point of the thermal bondable short fibers having the lowest melting point in the bonding layer by 30? C. or more. Further, the bonding layer preferably comprises two or more kinds of thermal bondable short fibers with a fineness difference of more than or equal to 5 dtex.

Claims

1. A filter reinforcing material comprising, a bonding layer comprising a thermal bonded nonwoven including thermal bondable short fibers, and a reinforcing layer comprising a nonwoven including high-melting fibers having a higher melting point than a melting point of thermal bondable short fibers having the lowest melting point in the bonding layer by 30? C. or more, wherein Metsuke of the filter reinforcing material is 40 to 120 g/m.sup.2, and the high-melting fibers comprise at least one selected from the group of (a) thermal bondable short fibers having a fineness of 1.0 to 40 dtex and a higher melting point than a melting point of the thermal bondable short fibers having the lowest melting point in the bonding layer by 30? C. or more and (b) non-bondable fibers having a fineness of 1.0 to 40 dtex and a higher melting point than a melting point of the thermal bondable short fibers having the lowest melting point in the bonding layer by 30? C. or more.

2. The filter reinforcing material according to claim 1, wherein the bonding layer comprises two or more kinds of thermal bondable short fibers with a fineness difference of more than or equal to 5 dtex.

3. The filter reinforcing material according to claim 1, wherein the reinforcing layer comprises the high-melting fibers by more than or equal to 60 weight % out of 100 weight % of fibers contained in the reinforcing layer.

4. The filter reinforcing material according to claim 1, wherein, melting point of the thermal bondable short fibers in the bonding layer is 80 to 150? C., and content of the thermal bondable short fibers in the bonding layer with a melting point of 80 to 150? C. is 60 to 100 weight % out of 100 weight % of fibers contained in the bonding layer.

5. The filter reinforcing material according to claim 1, wherein average fineness of fibers contained in the reinforcing layer is larger than average fineness of fibers contained in the bonding layer.

6. The filter reinforcing material according to claim 1, wherein the bonding layer and the reinforcing layer are integrated by thermal fusion bonding.

7. The filter reinforcing material according to claim 1, wherein the thermal bondable short fibers in the bonding layer are composite fibers with core-sheath structure, eccentric structure, or side-by-side structure.

8. A filter medium for deodorizing filter comprising, the filter reinforcing material according to claim 1, an adsorbent layer comprising adsorbents laminated on the side of the bonding layer of the filter reinforcing material, and a base material laminated to sandwich the adsorbent layer with the filter reinforcing material.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described more specifically by way of examples. The present invention is not limited to examples described below, and can also be carried out with appropriate modifications within the range adaptable to the gist described above and below, and such modifications are included in the technical scope of the present invention. For reference, in the following, unless otherwise noted, part means weight part, and % means weight %.

(2) Evaluations of Examples and Comparative examples are as follows. 1. Metsuke (mass per unit area): According to JIS L1913 6.2. 2. Thickness: According to JIS L1913 6.1.1 A method. The pressure applied to test piece is 2 g/cm.sup.2. 3. Peel strength: The filter medium for deodorizing filter is used and measured according to JIS L1086 7.10. The size of the test piece is 50 mm wide, and 200 mm long. Peeling speed is 100 mm/min. 4. Bending strength: As a sample, the filter medium for deodorizing filter cut to a size of 80 mm in length?65 mm in width is used. When preparing the sample, length and width of the sample are made corresponding to the machine direction (MD) and cross machine direction (CD) of the fiber sheet, respectively. The sample is folded with a mountain fold at the half position from both ends in length direction, so that the sample is made a size of 40 mm in length?65 mm in width. In a state in which the mountain parts of the folded sample is turned upwards, it is set in a rectangular frame with a size of 40 mm in length?65 mm in width, so that length direction and width direction of the sample are corresponding to length direction and width direction of the frame, respectively. On the other hand, the compression jig with a tip of ?10 mm is attached to the upper grip of the tensile testing machine. The compression jig is pressed against the center of the mountain parts of the sample in the width direction and moved downward at a speed of 50 mm/min. The load at that time is measured, and the maximum measured value is determined as the bending strength. 5. Peeling at the time of pleating: The filter medium for deodorizing filter was slit to a width of 250 mm, and creased so that a height of pleats was 28 mm, and the pleats were formed. The peeling state at that time is evaluated using the following symbols. A: No Peeling occurred, the mountain parts and the valley parts of the pleats were quite sharp, and the pleats were fairly neat. B: Peeling did not occur, the mountain parts and the valley parts of the pleats were sharp, and the pleats were neat. C: Some peeling occurred or there were some peeling-like parts, and there were some parts where the mountain parts and the valley parts of the pleats were not sharp or the pleats were not neat. (Standard) D: A lot of peeling occurred and it could not be processed, and there were a lot of parts where the mountain parts and the valley parts of the pleats were not sharp or the pleats were not neat. 6. Pleat adhesion at the time of heat setting: After the evaluation of 5. Peeling at the time of pleating, heat setting is performed at the temperature shown in Table, and Pleat adhesion at the time of heat setting is evaluated using the following symbols. B: Pleat adhesion did not occur. The shape of pleats and pleating property were good. D: Pleat adhesion occurred. The shape of pleats and pleating property were bad. 7. Shape after heat setting: After the evaluation of 5. Peeling at the time of pleating, heat setting is performed at the temperature shown in Table, and Shape after heat setting is evaluated using the following symbols. A: Pleats were regularly arranged in good order, and the shape of pleats and pleating property were quite good. B: Pleats were almost regularly arranged in good order, and the shape of pleats and pleating property were good. C: There were some parts where pleats were not regularly arranged, but the shape of pleats and pleating property were practical level. (Standard) D: There were many parts where pleats were not regularly arranged, and the shape of pleats and pleating property were bad. 8. Pressure loss of the unit: After the evaluation of shape after heat setting, general-purpose frame materials are attached to four sides to produce a unit of pleated air filter. Pressure loss (Ps) in Examples and Comparative examples is evaluated using the following symbols by difference from pressure loss (Ps) in Reference example which corresponds to standard. A: Decreasing rate of pressure loss was higher than 5%, and quite better than standard. B: Decreasing rate of pressure loss was higher than 0% and lower than or equal to 5%, and more than or equal to standard. C: Standard D: Pressure loss was larger than standard.

(3) For reference, decreasing rate of pressure loss (%)=(Ps-Ps)/(Ps)?100. 9. Comprehensive evaluation: Whether it is suitable as a pleated air filter or not is evaluated using the following symbols. A: Quite suitable as the pleated air filter B: Suitable as the pleated air filter C: A little problem as the pleated air filter (standard) D: Not suitable as the pleated air filter

(4) Fibers used in Examples and Comparative examples of the present application are summarized below. For reference, the thermal bondable short fibers (a) to (e) are polyester fibers with core-sheath structure having a composition ratio of 50(core)/50(sheath), and are the fibers of which core component is polyethylene terephthalate and of which sheath component is modified polyester having a melting point shown in Table 1 below.

(5) TABLE-US-00001 TABLE 1 Melting point Fineness Fiber length Fibers Components Structure (? C.) (dtex) (mm) Thermal bondable fiber (a) Polyester Core-sheath 110 2.2 51 Thermal bondable fiber (b) Polyester Core-sheath 110 17 51 Thermal bondable fiber (c) Polyester Core-sheath 150 4.4 51 Thermal bondable fiber (d) Polyester Core-sheath 150 2.2 51 Thermal bondable fiber (e) Polyester Core-sheath 180 22 64 PET fiber (f) Polyester Single 260 17 51

Example 1

(6) As the bonding layer and the reinforcing layer, weighing and mixing were performed according to each the fibers and weight ratio shown in Table to produce cross-laid fiber webs, and then laminated. After laminating, heat treatment was performed for 30 seconds at a heat treatment temperature of 200? C. to produce the filter reinforcing material.

(7) On the side of the bonding layer of the produced filter reinforcing material, 280 g/m.sup.2 of the functional material, which is a mixture of the coconut shell activated carbon (average particle diameter 400 ?m) and the polyester-based thermoplastic resin powder (particle size distribution 100 to 150 ?m) with a weight ratio of 1:0.05, was sprayed. After spraying the EVA-based thermoplastic resin powder on that, the base material which is consisted of the electret processed spunlaid nonwoven made of polypropylene (PP) was laminated, and heat treatment at 130? C. shown in Table 2 for integrating, to produce the filter medium for deodorizing filter.

Examples 2 to 8 and Comparative Examples 1 to 2

(8) In the same manner as Example 1 except that the conditions shown in Table 2 were changed, the filter reinforcing material and the filter medium for deodorizing filter were manufactured.

Reference Example

(9) As the reinforcing layer, weighing and mixing were performed according to the fibers and weight ratio shown in Table 2 to produce cross-laid fiber webs, heat treatment was performed for 30 seconds at a heat treatment temperature of 200? C. On that, the polyester type thermal bondable filament nonwoven (Dynac?: melting point 120? C.) was laminated as the bonding layer, heat treatment was performed at 140? C. to produce the filter reinforcing material.

(10) TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Co. 1 Co. 2 Ref. Filter Constitution Bonding Thermal bondable fibers (a) 110? C. 2.2dtex (%) 30 70 30 30 30 30 30 30 30 0 0 reinforcing layer Thermal bondable fibers (b) 110? C. 17dtex (%) 70 30 50 50 70 70 70 70 70 0 0 material Thermal bondable fibers (c) 150? C. 4.4dtex (%) 0 0 0 0 0 0 0 0 0 35 0 Thermal bondable fibers (e) 180? C. 22dtex (%) 0 0 20 20 0 0 0 0 0 65 0 Dynac? (g/m.sup.2) 10 Metsuke of thermal bondable short fibers (g/m.sup.2) 36 25 29 29 37 40 18 60 35 0 10 with a melting point of 80 to 150? C. Metsuke of bonding layer (g/m.sup.2) 36 25 36 36 37 40 18 60 35 35 10 Reinforcing Thermal bondable fibers (a) 110? C. 2.2dtex (%) 0 0 0 0 0 0 20 0 30 0 0 layer Thermal bondable fibers (b) 110? C. 17dtex (%) 0 0 0 20 0 0 0 0 70 0 0 Thermal bondable fibers (c) 150? C. 4.4dtex (%) 35 35 35 35 30 35 30 0 0 35 35 Thermal bondable fibers (d) 150? C. 2.2dtex (%) 0 0 0 0 0 0 0 100 0 0 0 Thermal bondable fibers (e) 180? C. 22dtex (%) 65 65 65 45 50 65 50 0 0 65 65 PET fibers (f) 260? C. 17dtex (%) 0 0 0 0 20 0 0 0 0 0 0 Mixing ratio of high-melting fibers (%) 100 100 100 80 100 100 80 100 0 0 Metsuke of reinforcing layer (g/m.sup.2) 35 25 35 35 35 32 54 10 35 36 60 Total Total metsuke (bonding layer + reinforcing layer) (g/m.sup.2) 71 50 71 71 72 72 72 70 70 71 70 Bonding layer: Reinforcing layer (ratio of metsuke) 50:50 50:50 51:49 51:49 51:49 56:44 25:75 86:14 50:50 50:50 14:86 Manufacturing Heat treatment temperature (? C.) 200 200 200 200 200 200 200 200 200 200 200 conditions Filter Constitution Metsuke of (adsorbents + adhesive resin) (g/m.sup.2) 280 280 280 280 280 280 280 280 280 280 280 medium for Metsuke of base material (g/m.sup.2) 20 20 20 20 20 20 20 20 20 20 20 deodorizing Materials for base material PP PP PP PP PP PP PP PP PP PP PP filter Manufacturing Heat treatment temperature 130 130 130 130 130 130 130 130 130 130 130 conditions Pleated Manufacturing Temperature at the time of heat setting (? C.) 100 100 100 100 100 100 100 100 100 100 100 unit conditions Property Thickness (mm) 1.0 0.8 1.0 1.0 1.1 1.0 1.0 1.1 1.0 1.3 1.0 Peel strength (N/50 2.06 2.00 1.80 1.85 2.06 2.21 1.55 2.30 2.08 0.66 1.50 mm) Bending strength (N) 1.50 1.15 1.35 1.45 1.43 1.59 1.33 1.54 1.53 0.43 1.20 Peeling at the time of pleating A A A A A A B A A D C Pleat adhesion at the time of heat setting B B B B B B B B D B B Shape after heat setting A A A A A A B A D D C Pressure loss of the unit A A A A A A B B D D C Comprehensive evaluation A A A A A A B B D D C