JPH0135937B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nonwoven fabric sheet incorporating powder or granules having functions such as adsorption, absorption, and fragrance, and a method for manufacturing the same. More specifically, an aggregate of substantially long filaments is widened and opened to form a thin web with a uniform thickness and a constant width, and the fiber layer is advanced onto a drive belt with or without applying an adhesive or solvent to the surface of the fiber layer. At the same time, the powder or powder is uniformly spread over the fiber layer in a predetermined width so that the vertical and horizontal cross sections of the laminate form an oblique layer. The present invention relates to a nonwoven fabric that is alternately laminated and then molded, and a method for producing the same.

BACKGROUND ART Conventionally, in order to efficiently utilize powders or granules having functions such as adsorption and absorption, it has been common practice to fix them together with fibrous materials in the form of a sheet. Although various methods have been studied and some methods have been developed, there are still many unresolved problems in terms of quality and manufacturing process. For example, in the case of a so-called wet method using water as a dispersion medium, pulp and powder or granules are dispersed in water to form a uniform dispersion medium layer, and then a nonwoven fabric sheet is manufactured using a paper machine. However, this type of wet method usually does not use a binder and the shape is maintained and the added powder or granules are supported by intertwining the fibers, so the sheet density and rigidity are generally high, making it suitable for various uses. However, it is unsuitable when a low resistance value is desired, such as when passing through gas. Further, since it is difficult to add a large amount of powder or granules, a large amount of nonwoven fabric sheet is required to improve the performance of the added powder or granules, which is not preferred in practice. In addition, there are many other drawbacks such as outflow of powder or granules during the dehydration process and non-uniform layer distribution due to the difference in specific gravity between the additive and the fibers.

In contrast to the wet method, the dry method uses powder or granules,
Japanese Patent Laid-Open No. 53-4789 discloses a method in which wood pulp and thermofusible synthetic pulp are added to a support layer and supported, and then heated with hot air to melt the fusible synthetic pulp and mold the whole with adhesive. It has been disclosed. In this patent, the active surface area of the adsorptive substance is kept large to prevent a decrease in activity and to achieve efficient adsorption, but this method of laminating layers with an air medium makes the adsorption substantially uniform due to the difference in specific gravity of the constituent materials. It is difficult to distribute the powder or granules evenly, and the amount of powder or granules added cannot be said to be sufficient. As mentioned above, it is considered that an economical industrial production method for nonwoven fabrics in which a large amount of powder or granules is present as a uniform layer within the fiber layer has not yet been established in view of these points. The present invention is the result of intensive research aimed at developing a nonwoven fabric sheet that has a higher content of powder or granules than conventional nonwoven fabrics and is superior in quality, as well as a method for efficiently manufacturing the nonwoven fabric sheet. discovered a method of producing a nonwoven fabric containing powder or granules by a dry method using a filament aggregate, and arrived at the present invention.

The present inventors have previously discovered an efficient method for producing a nonwoven fabric sheet from a filament fiber aggregate, and filed an application for this method in Japanese Patent Application No. 42412/1983. In this method, a web made of filament aggregates is introduced onto a driving belt, and the webs are laminated on the driving belt at a certain angle, for example, perpendicular to the direction of travel of the belt, and then formed. .

The present invention is a nonwoven fabric that incorporates powder or granules in a layered manner by layering powder or granules on the web while scattering them in a width narrower than the web width, and then molding the nonwoven fabric in the manufacturing process of the above-mentioned nonwoven fabric. You get a sheet.

In the nonwoven fabric sheet of the present invention, the surface layer is composed only of fibers, and powder or granules are included therein in a layered manner inclined in the thickness direction.

That is, the powder or granules in the present invention are structured to form diagonal layers in the fiber layer. As can be seen in the sectional view shown in FIG. 1B, a powder or granule layer 21, indicated by a dot, is surrounded and supported by a fiber layer 22. This configuration of the present invention is characterized by the fact that each layer 21 is surrounded by a layer 22, thereby providing great stability, and that a large number of layers 21 can be included. In addition, the effects that can be expected from this diagonal layer are, for example, when the adsorbent is added as granules. The contact time between the adsorbent substance and the adsorbent particles can be made longer when an obliquely inclined layer is formed than when the adsorbent particles are formed. Furthermore, since the adsorbed substance collides with the slope of the adsorbent particles, there is an advantage that gas ventilation resistance is reduced. Therefore, the nonwoven fabric sheet produced with these features of the present invention can be used to achieve very efficient results when using physical and chemical effects to permeate and adsorb various gases and liquids. It is extremely useful. Furthermore, when the fibers forming the fibrous layer 22 are formed from continuous substantially long filaments, fluff, lint, etc. are not scattered, and a high-quality nonwoven fabric sheet with extremely low lint waste can be obtained.

In addition, the reason why we are able to manufacture this excellent nonwoven fabric sheet is that we supply continuous fibers without cutting them, and meet certain conditions such as thickness, density,
This is because the width, added weight, etc. can be freely controlled to the desired properties, and continuous,
It is an extremely economical manufacturing method as it allows for mass production.

That is, in the present invention, one of the vertical and horizontal cross sections of the nonwoven fabric sheet is composed of inclined powder layers or granular layers alternating with fiber layers, and the other cross section is composed of horizontal powder layers or granular layers. A nonwoven fabric sheet consisting of alternating layers with fiber layers, the outermost layer being the fiber layer, and the method for producing the nonwoven fabric includes:
The process of supplying a widened and opened continuous fiber layer onto the drive belt by dispersing powder or granules onto the fiber layer using a dispersion pipe attached to a tossing device, and the above process. This method of producing a nonwoven fabric is characterized by comprising a molding step of forming a molded sheet from the obtained alternating laminate of fiber layers and powder layers or granule layers.

The present invention will be explained in more detail. The types of fibers used in the present invention include semi-synthetic fibers such as rayon and cellulose acetate fibers, synthetic fibers such as polyamide, polyester, and polypropylene, and two components consisting of a cellulose acetate fiber component and a polyacrylonitrile component in a single yarn. Composite fibers having various structures, or a mixture of two or more thereof, which form a continuous tow-like fiber bundle, may be used. Further, crimped fibers are suitable, but uncrimped fibers can also be used. The thickness of the fiber is
It can be used in the range of 0.1 denier to 100 denier, preferably 0.1 denier to 50 denier, and in the range of 1000 denier to 3,000,000 denier, preferably 5000 denier to 500,000 denier for the whole fiber. If the single yarn denier is too large, the powder or granules may fall off or stand out from the molded nonwoven fabric sheet, which is unfavorable in terms of quality. Furthermore, if the total fiber size exceeds 3,000,000 deniers, the fiber bundle will become too large and will not be opened sufficiently with a normal fiber opening machine, and restrictions will be imposed on the equipment, which is not economically advantageous.

In the present invention, when it is necessary to use an adhesive or a solvent as a binder for the fibers constituting the nonwoven fabric sheet, the adhesive is usually a liquid adhesive such as vinyl acetate resin emulsion or a solid adhesive called hot melt. As the material, a material having the property of partially melting the fiber surface and then evaporating is used. Further, depending on the type of fiber, an adhesive and a solvent may be used together as a binder.

Various substances can be used as the powder or granules used in the present invention depending on the purpose of use. For example, substances such as activated carbon, diatomaceous earth, activated alumina, acid clay, and silica gel are materials that have a very large active surface within their structure and exhibit strong adsorption properties. Substances called high-molecular water-absorbing polymers that exhibit properties such as polyacrylonitrile-modified starch,
Examples include cross-linked carboxymethyl cellulose and cross-linked polyethylene oxide. Other powders or granules that have insect repellent, insecticidal, repellent or attractive effects, aromatic properties, etc. The powder or granules themselves do not exhibit any effect, but are simply impregnated with liquids that have various effects as a support. Also available.

The nonwoven fabric sheet of the present invention and its manufacturing method will be specifically explained below with reference to the drawings.

Figure 1 is a cross-sectional view of the nonwoven fabric sheet of the present invention, Figure A is a cross-sectional view cut at an angle perpendicular to the direction of production of the nonwoven fabric sheet, and Figure B is a longitudinal cross-sectional view cut parallel to the direction of travel of the nonwoven fabric sheet. In the plan view, a layer 21 indicated with a dot indicates a layer consisting of a powder or granule layer, and an outlined layer 22 indicates a fibrous layer.

The structure in which the powder or granule layer 21 is inclined obliquely and is surrounded by the fiber layer 22 shown in FIG. Consideration is given so that the substance and the powder or granules can be in contact with each other for a long time and at a long contact distance. Also, Figure A,
In Figure B, since the powder or granule layer is divided into small layers and each layer is surrounded by a fiber layer 22, it is possible to support a surprisingly large amount and in a stable state as a whole. Usually, the proportion of additives to the fiber weight is 30 to 500 wt.%,
500wt.% or more is not impossible but can be used.

The scope of use of the nonwoven fabric sheet is not particularly limited, but as one specific use, for example, when used as an additive with activated carbon, a nonwoven fabric sheet that can be used as a deodorizing mat can be obtained.
Furthermore, if an aromatic substance is added, it can be used as an aromatic agent. Additionally, if silica gel is added, it can be used as a desiccant agent.

Figure 2 shows the process of taking out the encased fibers.
It is a process schematic diagram showing the first half of the process of the present invention up to the swaying process. Reference numeral 1 denotes a raw material fiber bundle taken out from the fiber bundle. Here, the case of cellulose acetate fiber will be specifically described. Fiber 1, which has a single yarn denier of 4 denier, a total fineness of 43,000 denier, and a number of crimps of 28 per inch, is widened by a spreader 2, passed through a guide roll, and then passed through a pair of pressure rolls 3 and 4. The fibers are opened by applying tension in the direction of travel. Next, through a pair of rolls 5, triacetin is applied as an adhesive or solvent to the roll surface from a coating equipment 6 attached to the rolls, and approximately 20 wt.% of triacetin based on the fibers is transferred from the roll surface to the fiber surface. The purpose of applying an adhesive or solvent to the fibers is to cause bonding between the single fibers and form a three-dimensional network composition. A similar effect can also be achieved by mixing and heating the fibers.

Application methods other than the one used here include the spraying method and the method of adding adhesive solid particles, but these have many drawbacks.For example, the spraying method using a spray gun has problems with the adhesive due to the atomization of the adhesive during spraying. This causes loss and stickiness of the equipment due to adhesion to the surrounding areas, resulting in poor workability. The method of mixing a hot-melt type solid powder or granular adhesive into an additive material and dispersing it in a tossing process is not a very good method because the active surface of the additive material is heavily contaminated.

Another advantage of the method of forming the network composition used in the present invention, which involves applying an adhesive or solvent to the fiber surface, is its antistatic effect. Fibers are generally easily charged, and even in the case of the present invention, processes that are likely to be charged, such as fiber opening treatment and roll transport, are included. Due to the static electricity generated in such a case, the aggregate of fibers becomes bulky and repulses each other, causing problems in the following steps, which are the twilling lamination step and the additive dispersion step. Therefore, the addition of an adhesive or solvent that exhibits such an antistatic effect not only makes it possible to carry out at least the swaying work and the lamination work process smoothly, but also the addition of such an adhesive or solvent that exhibits an antistatic effect. It is surprisingly possible to uniformly and stably add it onto the fibers.

Following the above steps, the fiber layer that has passed through a pair of feed rolls 7 is introduced into a traversing device 14. FIG. 4 shows a perspective view of the main parts of the traversing process. The swinging device 14 is a wide rectangular tube through which the opened fiber layer passes, and is capable of so-called oscillating motion by an attached swinging piston 16, and the square tube is also filled with powder or granules. A powder or granule spreading tube 17 is provided for spreading onto the fiber layer. The dispersion pipe has 2 parts in the center.
It is designed to distribute the material to the left and right as the direction of the swing changes. Further, a powder or granule feeding device 15 is attached above the dispersion pipe to quantitatively supply the substance to be sprayed. One end of the feeding device is located at the upper center of the spraying pipe 17, and is designed so that the substance to be sprayed can fall into either the left or right side of the spraying pipe 17 as the swinging direction changes, and the spraying pipe It is necessary to make the width of the nonwoven fabric sheet narrower than the width of the fiber layer, and by making it narrower, the edge of the fiber layer forms a part that does not contain the substance to be dispersed, and the surface of the nonwoven fabric sheet is formed with a layer of only fibers. become.

Powder or granules are sprinkled on the inside of the folded fiber layer at any time, and are added intermittently so that the scattering is stopped when the fiber layer is folded back so as not to spill out from the fiber layer. The time for this intermittent spraying differs depending on the type of substance to be sprayed, so it must be adjusted according to each condition.

When the twisted fiber layer is guided to the drive belt 8 and laminated, the drive belt end, ie,
Disturbances may occur at the folds of the fiber layer, which may cause spillage of the sprayed material. In order to prevent such troubles, an ear pressing device 9 is provided in the present invention. In addition, fiber layers such as nylon fibers and polypropylene fibers become much bulkier due to cellulose acetate fibers due to fiber opening, but in such cases, the selvage pressing device 9 is very effective even if the introduction speed is low. be.

FIG. 3 is a process schematic diagram showing the second half of the process of the present invention after the zigzag process. The fiber layer 2 passes through the waving device 14, is laminated onto the drive belt 8 while containing the substance sprayed from the spray pipe 17, and is transported in a molding process.

For the purpose of reducing the bulk of the laminated fibers, an air suction device 13 may be installed directly below the twirling device 14 and on the back side of the drive belt to suck the tangled fiber layer.

The drive belt 8 is preferably made of wire mesh or the like so that operations such as heat treatment in the molding process can be easily carried out. The molding process is carried out between a wire mesh drive belt 8 installed on a fixed table and a wire mesh drive belt 10 installed on an up-and-down movable table, and the thickness and density of the nonwoven fabric sheet are determined depending on the distance between the two belts. You can make adjustments. To perform molding by heating, heating bars may be used singly or in pairs, or two or more heating bars; in this example, one pair of heating bars
A heating device consisting of a pair of heating bars 11 and 12 performs a thermoforming process on both sides of the laminated fiber layer. The heating medium used here can be hot air or superheated steam with good thermal efficiency.

In the present application, hot air is used to forcefully dry the nonwoven fabric sheet in order to remove moisture remaining in the nonwoven fabric sheet after it is molded using a steam heat treatment method.

After the molding process, although not shown in the drawings, cutting and rolling are performed as necessary, followed by packaging.

Note that the first half process of the present invention shown in FIG. 2 and the second half process of the present invention shown in FIG. has been done.

FIG. 4 is an enlarged perspective view of the main part of the traversing process.

The opened fiber layer 2 is agitated by the operation of the piston 16 and is laminated onto the drive belt 8, and at the same time contains the substance that is spread from the powder or granule feeding device 15 using the spreading pipe 17. After the disorder of the folded portion of the fiber layer is corrected by the edge pressing device 9, the angle θ at which the fiber layer is stacked, which proceeds to the molding process as the belt moves, can be arbitrarily set to be large or small depending on the specifications of the nonwoven fabric sheet. The desired angle can be adjusted by belt speed and fiber feed speed.

Point A is the end of the fiber layer, and care must be taken to ensure that point A does not go beyond point B at the end of the material to be sprayed and into the center. If the adjustment is incorrect, scattered substances will appear on the surface of the nonwoven fabric sheet, resulting in a defective product.

The angle θ is preferably substantially 5° or less, and is usually adjusted so that the number of fiber layers stacked is from 5 to about 10. As the number of layers increases, the fiber layers become bulkier, which naturally makes the lamination work more difficult. Here, the blower of the air suction device 13 is operated as necessary to suck the laminated fiber layers, thereby reducing the thickness of the layers.

The specifications of the nonwoven fabric sheet include the type and fineness of the fibers, the type and particle size of the powder or granules, the driving speed of the drive belt 8, the feeding speed of the powder or granules feeding device 15, and the traversing of the swaying device 14. It can be freely controlled by selecting conditions such as speed.

The present invention will be described below based on Examples, but it is not necessarily limited to the Examples, and changes and modifications within the spirit and scope of the invention are included within the technical scope of the present invention.

Example 1 For the purpose of creating a superstructure in which activated carbon is supported between fiber layers in multiple thin layers, a nonwoven fabric sheet with fiber layers made of cellulose acetate fibers was created.

The cellulose acetate fiber used had a denier of 4, a total denier of 43,000, and a crimp number of 28/inch. Granular coconut shell charcoal of 40 to 80 mesh was used as the activated carbon.

The fiber bundle is opened and hetriacetin is applied to both sides of the fiber layer. Application amount is 20wt.% of fiber weight (external division)
It is. The drive belt speed was set so that the fiber layer feeding speed was 60 m/min, and the nonwoven fabric sheet thickness was set to 9.
The distance between the drive belts 8 and 10 was set to be m/m. The fiber layer was twisted so that the fiber basis weight was 900 g/m ² and the activated carbon weight was 630 g/m ² .
Carbonaceous charcoal was spread and formed into alternating layers. Pressurized steam (1Kg/
cm ³ ) was used. By this molding method, the fibers were well bonded to each other and formed into a network shape. This non-woven fabric sheet had good air permeability and was extremely suitable as an overbody for indoor tobacco smoke and deodorization due to the adsorption power possessed by the activated carbon.

Example 2 The fibers used in the fiber layer were cellulose acetate fiber (single thread thickness: 2.2 denier, total fineness: 40,000 denier, number of crimps: 20/inch) and polypropylene fiber (single thread thickness: 2.0 denier, Total fineness: 10000, number of crimp: 10
The material used in the form of powder or granules was cross-linked carboxymethyl cellulose granules with high water absorption.

After each of the above-mentioned fibers was individually widened and opened, and both fiber layers were merged, triacetin was applied to both sides of the layer in an amount of 18% (external division) based on the weight of the fibers using a binder coating device.

The manufacturing conditions were set such that the fiber layer feeding speed was 60 m/min, the belt interval was 7 m/m, the fiber basis weight was 500 g/m ² , and the crosslinked carboxymethyl cellulose was 250 g/m ² , and the fibrous layers were alternately laminated. It was molded using pressurized steam (1 Kg/cm ² ).

The produced nonwoven fabric sheet was cut into rectangles 5 cm wide and 15 cm long, wrapped for the purpose of use as a menstrual blood absorption agent, and used as sanitary napkins.
We obtained an extremely excellent product as a napkin, which has very good blood absorption performance and has excellent cushioning properties on the body side.

[Brief explanation of drawings]

FIGS. 1A and 1B are cross-sectional views of the nonwoven fabric sheet of the present invention, and A is a cross-sectional view cut perpendicular to the direction of travel of the drive belt. B is a cross section cut in the same direction as the belt traveling direction. Second
3 and 3 are schematic process diagrams of the manufacturing method of the present invention. In particular, FIG. 2 shows the first half from the beginning to the traversing process, and FIG. 3 shows the second half from the zigzag process to the molding process. FIG. 4 is a perspective view of the main part of the traversing process. 1... Fiber bundle, 2... Expander, 3, 4, 5, 7
...Pressure roll, 6...Coating equipment, 8,10...
Drive belt, 9... Ear pressing device, 11, 12...
Heating bar, 13...Suction device, 14...Twiddling device, 15...Powder or granule feeding device, 16...
...Piston device, 17...Powder or granule dispersion pipe.

Claims (1)

[Scope of Claims] 1. A nonwoven fabric sheet containing powder or granules formed by folding and laminating a wide web of substantially long filament aggregates, the powder or granules comprising:
A nonwoven fabric sheet characterized by being constructed in layers that are inclined in the thickness direction. 2. Spreading a substantially long filament assembly;
The web, which has been widened to a certain width, is rolled over the drive belt and laminated, and at the same time, powder or granules are scattered onto the web layer in a width narrower than the web width, and the web layer and the additive layer are alternately laminated. A method for producing a nonwoven fabric sheet, which is then formed by causing interfiber adhesion using a heating medium such as hot air or steam. 3 The direction of crisscrossing in the web lamination process is
The method for manufacturing a nonwoven fabric sheet according to claim 2, which is perpendicular to the traveling direction of the drive belt.