JPS6351725B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a material used in an air cleaner for an automobile engine or an air cleaner for an air conditioner, and specifically relates to an improvement in a density gradient type nonwoven fabric constituting the material. Conventionally, this type of material has a fiber layer with a large diameter on the upstream side of the incoming air, a fiber layer with a small diameter on the downstream side, and a fiber layer with a diameter about the middle of the two in between. A density gradient type nonwoven fabric is used by laminating and integrating the multilayered fiber layers using needle punching and a resin adhesive. In the above materials, in order to ensure cleaning efficiency, a fiber layer with a narrow diameter is used on the downstream side of the incoming air to increase the density, but as the thickness of this fiber layer becomes thinner, the fiber layer itself becomes sheet-like. However, local layer unevenness occurs, making it difficult to maintain cleaning efficiency.
For this reason, it is necessary to increase the thickness of this fiber layer (for example, about 0.5 to 1.0 mm) to maintain cleaning efficiency. The total layer thickness including the layers increases. In general, surface-filtered materials may be preferable for air purifier materials depending on the environmental conditions in which they are used.
To achieve this type, it is necessary to reduce the layer thickness of the material and increase the overarea. Therefore, it is not desirable to increase the thickness of the entire material by increasing the thickness of the fiber layer with a narrow diameter on the downstream side of the air as described above. For this reason, the current situation is to reduce the thickness of the large-diameter fiber layer and the intermediate layer on the upstream side of the air, but this poses problems in terms of the amount of dust retained and shortened service life. ing. In addition, in conventional products, each fiber is composed of short fibers, and since the fiber gaps are uneven, it is necessary to increase the overall accuracy, so a large amount of resin adhesive is used to fill the fiber gaps. This has the disadvantage of increasing costs due to the large consumption of resin adhesive. Furthermore, as a large amount of resin adhesive is used, the gaps between the fibers may partially be completely closed, which has the disadvantage of shortening the service life. In order to solve the above-mentioned problems, the present invention has a structure in which, on one side of the intermediate fiber layer made of short polyester fibers,
Sheet-like spunbond fiber layers made of thermoplastic synthetic fibers whose interfibers are partially fixed by heat fusion are laminated, and on the other side of the intermediate fiber layer, a fiber layer made of short polyester fibers is laminated. are laminated, the thickness and fiber amount of each fiber in each fiber layer are selected, and each fiber is partially stacked from the fiber layer side on the other side of the intermediate layer toward the lamination direction of each fiber layer. By intertwining and integrating the fibers of the layers and applying a predetermined amount of resin adhesive, we have created an air purifier material that can increase the amount of dust retained, extend its life, and reduce the amount of resin adhesive. The purpose is to provide In the present invention, the spunbond fiber layer is produced, for example, as follows. That is, for example, a polyester polymer is melted, and while flowing through the pores of a metal ring plate, it is stretched with a jet flow of air to form ultrafine and long fibers, which are then stacked on a moving screen so that the fibers are folded over each other. A portion (5 to 20% of the total) is thermally melted and partially heat-sealed. As a result, a spunbond fiber layer in which polyester long fibers are formed into a sheet is obtained. In this fiber layer, the fibers themselves are long, and the fibers are partially heat-fused, so even if the layer is thin, it forms a sheet, and the gaps between the fibers allow the fibers to be partially heat-fused. As a result, the layer becomes almost uniform and its density increases, resulting in better cleaning efficiency and accuracy than a fiber layer made of short fibers. Further, as described above, since the spunbond fiber layer can be made thinner, the thickness of other fiber layers laminated on this fiber layer can be increased. As mentioned above, the other fiber layers are made of short fibers (for example, 20 to 60 mm) and have a cotton-like appearance, but this and the fact that the layer thickness can be increased combine to reduce the amount of dust retained. It can be made larger and therefore has a longer lifespan. Furthermore, by adopting a spunbond fiber layer, as mentioned above, it is possible to make this fiber layer thinner, so the overall material including other fiber layers laminated on top of this fiber layer can be made thinner. The layer thickness can be made thinner than in the past, and therefore it can be used for surface overlapping types with large overlapping areas. Furthermore, in the present invention, since overaccuracy is ensured by the spunbond fiber layer, it is necessary to increase the amount of resin adhesive attached to the entire fiber layer and fill the gaps between the fibers with the adhesive to make them smaller. Therefore, the resin adhesive only needs to be used in an amount that is sufficient to bond the fiber layers together and increase the overall rigidity. Therefore, the total volume of the gaps between the fibers in the material can be increased compared to the conventional method. From this point of view as well, the lifespan can be extended. Furthermore, since only a small amount of resin adhesive is required, costs can be reduced. In the present invention, the fiber layers are integrated with each other by needle punching as shown in FIG. That is, in FIG. 1, an upper layer 1 made of a polyester short fiber layer with a large diameter, an intermediate layer 2 made of a thin polyester short fiber layer, and a sheet-like lower layer 3 made of a spunbond fiber layer are as shown in FIG. The layers 1, 2, and 3 are stacked, and each layer 1, 2, and 3 is needle punched using a needle 4 to integrate them. In other words,
By inserting the needle 4 in the stacking direction of each layer 1, 2, and 3 from the upper layer 1 side and pulling out the needle 4,
In the portion where the needle 4 is inserted, the fibers of each layer 1, 2, and 3 are entangled with each other to form an entangled portion a. In the present invention, each layer 1,
2 and 3 are bonded to each other, so each layer 1, 2, 3
Delamination is less likely to occur. Note that the overall thickness after needle punching is preferably 1.7 to 2.5 mm. If it is less than 1.7mm, there will be insufficient rigidity when folding, and if it is less than 2.5mm.
Exceeding this is not preferable because the excess area after pleating becomes small. In the present invention, the blending ratio of fibers, the thickness of fibers, and the amount of fibers in each fiber layer are selected as follows. That is, in order to improve the amount of dust retained, polyester fibers are generally used, which have a small increase in pressure loss when loaded with dust. In addition, from the viewpoint of dust retention, it is necessary to form a fiber state with a large retention capacity, so short fibers (20 to 60 mm) with a cotton-like surface are used. Since the upper layer 1 in FIG. 1 is placed on the upstream side of the air, it must be able to retain a large amount of dust, and it is also necessary that the lower intermediate layer 2 and lower layer 3 are not burdened with dust retention. . From this, the upper layer 1 is composed of a mixed fiber of polyester short fibers having a diameter of 4 to 15 deniers and polyester short fibers having a diameter of 1 to 4 deniers. Incidentally, if only polyester staple fibers with a large diameter are used in the upper layer 1, the dust retention efficiency is poor, and if only polyester staple fibers with a small diameter are used, the dust retention efficiency is improved, but on the other hand, clogging occurs due to dust retention. In addition, the upper layer 1 simply has a diameter of 4 to 15 deniers,
Simply combining two types of polyester short fibers with different diameters of 1 to 4 deniers will easily cause the above problem depending on the ratio, so ) polyester staple fibers have a fiber content of 30 to 40 g/m ² and a thicker diameter side (4 to 15 g/m2).
(denier) polyester short fibers are 30-40g/ ^m2
of fiber is required. The fibers of the middle layer 2 are the same as the upper layer 1 in that polyester staple fibers are used, but since the middle layer 2 needs to capture finer particles of dust than the upper layer 1, the fibers of the middle layer 2 are made of short polyester fibers of 1 to 6 denier. using short polyester fibers. Further, the amount of fiber is required to be 40 to 60 g/m ² . The diameter of the spunbond fiber in the lower layer 3 is 0.5
~2 denier is desirable. If it is less than 0.5 denier, it will be too thin and dense, and if it exceeds 2 denier, there will be a problem in terms of cleaning efficiency. As mentioned above, this spunbond fiber layer is
Some of the long fibers are fixed by heat fusion,
The ratio is preferably 5 to 20%. If it is less than 5%, the gaps between the fibers become non-uniform, resulting in a decrease in overaccuracy and difficulty in forming a sheet. On the other hand, when it exceeds 20%, the density increases too much and premature clogging occurs. In addition, the material of this fiber layer may be polyester,
Further, nylon or polypropylene may be used, and in short, any thermoplastic synthetic fiber that can be heat-sealed may be used. In the present invention, thermoplastic and thermosetting resins such as acrylic esters, water-soluble phenols, mixtures thereof, and epoxy resins can be used as resin adhesives. The adhesion amount of this resin adhesive to the material is 40~
60g/ ^m2 is desirable. By the way, if it is less than 40g/ ^m2 , the hardness (rigidity) of the material will be insufficient. For example, if the material is pleated and made into over-element 5 as shown in Figure 2, the folds will stick together when the ventilation resistance increases. Undesirable. On the other hand, if it exceeds 60g/ ^m2 ,
It closes the gaps between the fibers in the lower layer, ie, the spunbond fiber layer, leading to a reduction in service life. The present invention will be explained below with reference to specific examples, and experimental results compared with conventional materials will also be explained. In an embodiment of the present invention, in FIG.
6 denier short polyester fiber (fiber length
Intermediate layer ²
A mixed fiber of 28 g/m ² of 1.5 denier polyester staple fibers (fiber length 35 mm) and 19 g/m ² of 1.5 denier rayon staple fibers (fiber length 32 mm) was used. Further, as the lower layer 3, 50 g/m ² of 1 denier polyester spunbond fiber was used. These upper layer 1, middle layer 2, and lower layer 3 were integrated by needle punching, and 50 g/m ² of an acrylic ester resin adhesive was applied to these integrated sheet materials to bond and bond each layer. According to the above configuration, the upper layer 1 side has a low density, and the lower layer 3 side has a low density.
It is a density gradient material in which the density increases toward the upper layer 1, and the upper layer 1 traps dust particles having a large particle size, and toward the lower layer 3, dust particles having a fine particle size are captured. The above layers 1, 2, and 3 are formed by needle punching so that the fibers of each layer are partially entangled from the upper layer 1 side in the stacking direction of each layer 1, 2, and 3, and the fiber density is high in the entangled portion, and The resin adhesive also adheres to the intertwined portions, resulting in an integrated material that is firmly bonded as a whole. Next, the results of an experiment comparing the performance of the material of the present invention having the composition described in the above example and a conventional material will be explained. Figure 3 shows the experimental conditions according to JIS D 1612 (air cleaner test method): 1800c.c. engine, maximum air volume 4.8m ³ /min, dust concentration 1g/m ³ (JIS class 8 powder), and increased ventilation resistance against dust load. This is the result of measuring. In FIG. 3, the vertical axis shows increased ventilation resistance ΔP, and the horizontal axis shows dust retention amount G. In the figure, A is an overbody made of 100% conventional Kotton Linterpulse paper, with a thickness of 0.7 mm and an overarea.
It is ^6300cm2 . B is a conventional oil-impregnated wet overbody, consisting of 50% cotton linter pulp + 50% 4 denier rayon (fiber length 60mm), with an overbody area of 5500cm ²
It is. In addition, C is a conventional three-layer density gradient nonwoven fabric overbody, with the upper layer being 50% 6-denier polyester (fiber length 51 mm) and 3-denier rayon (fiber length 51 mm).
The middle layer is made of 50% 3 denier polyester (fiber length 40 mm) and 50% 1.5 denier rayon (fiber length 30 mm), and the bottom layer is made of 1.5 denier rayon (fiber length 30 mm).
Made of 100% denier rayon (fiber length 30mm). The total thickness is 3.5mm, and the over area is 2000mm.
^cm2 . D is an overbody having the same composition as C above, with a total thickness of 2.0 mm and an overarea of 3100 cm ² . E is an overbody made of the material of the present invention having the above composition, and has a total thickness of 2.0 mm and an overbody area of 3100 cm ² . The results are shown in Table 1 and FIG.

[Table] In Table 1, ηi (%) is the initial cleaning efficiency expressed as the efficiency when 20 g of dust is supplied, and ηf (%)
indicates the full-life cleaning efficiency expressed as the efficiency at increased airflow resistance of 300 mmAq. As is clear from the results in Table 1 and Figure 3,
The overbody E made of the material of the present invention is the conventional overbody A,
It can be seen that, compared to B, C, and D, even though the excess area and thickness are small, the dust retention amount and cleaning efficiency are excellent.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the material of the present invention, including the process of needle punching.
FIG. 2 is a partial sectional view showing an overbody using the material shown in FIG. 1, and FIG. 3 is a characteristic diagram for explaining the effects of the present invention. 1... Upper layer, 2... Middle layer, 3... Lower layer, a... Intertwined part.

Claims (1)

[Claims] 1 Diameter thickness 1-6 denier and fiber content 40-40
A sheet consisting of an intermediate fiber layer made of 60 g/m ² polyester short fibers and thermoplastic synthetic fibers placed on one side of this intermediate fiber layer and partially fixed between the fibers by heat fusion. a spunbond fiber layer and a fiber layer disposed on the other side of the intermediate fiber layer, with a diameter of 4 to 15 deniers and a fiber content of 30 to 15 deniers.
40g/ ^m2 polyester staple fiber and diameter 1
a fiber layer consisting of a mixture of short polyester fibers having a denier of ~4 denier and a fiber amount of 30 to 40 g/m ² , and the intermediate fibers are arranged in the laminating direction of this fiber layer, the intermediate fiber layer, and the sheet-like fiber layer. The fibers of each fiber layer are partially intertwined with each other from the fiber layer on the other side of the layer to integrate each fiber layer, and 40 to 60 g/m ² of resin adhesive is attached to this integrated fiber layer. An air purifier material characterized by comprising: