JP5067808B2 - Perforated non-woven sheet and method for producing the same - Google Patents

Description

  The present invention is formed by the airlaid method, and (1) a top sheet used for sanitary goods, sanitary napkins, paper diapers, and other absorbent articles, or a second sheet disposed between the top sheet and the water absorbent, (2) Various interpersons, objective wipers (wet, dry), (3) drip absorbent sheet (fresh food rug), (4) various highly permeable packaging materials, cushioning materials, (5) adsorbent sheet ( The present invention relates to a perforated nonwoven fabric sheet used for, for example, a large surface area and a structure suitable for adsorption of malodorous gas and the like and high air permeability.

  Conventionally known methods for producing perforated nonwoven fabrics are as follows: (1) A method of perforating with an existing nonwoven fabric by a punching press or calendering, (2) a method using water flow, (3) stretching and splitting the nonwoven fabric And so on. In (1), although the accuracy of the hole is good, the perforated part is lost, which is contrary to resource saving. Increasing the perforated area increases the loss. In (2), a high-pressure water flow is required and the cost is high, and only a hole having a size of about several millimeters can be expected. In the case of (3), not only a special stretching machine is required, but also the accuracy and number of holes are difficult to control, which is not a general purpose means.

As a specific example of the perforated nonwoven fabric, a perforated nonwoven fabric described in Patent Document 1 (Japanese Translation of PCT International Publication No. 2002-527636) has been proposed as a top sheet for sanitary products such as diapers and sanitary napkins. This perforated nonwoven fabric is composed of continuous filaments (split yarns), that is, an SB nonwoven fabric (paragraph “0032” in the patent document), and is perforated with a high-pressure water stream after the water stream is divided (paragraph “ 0037 "). Further, according to Example 1 of the patent document (paragraph “0039” of the patent document), the radius r of holes = average 1.4 mm, the interval = 6 mm, and the opening area = 34%.
This perforated nonwoven fabric is finer by division and fine denier, so it is soft and supple, has high strength, and is a perforated nonwoven fabric, so it has good body fluid permeability and low wetback properties. Has been.
However, since the web formation when forming the nonwoven fabric is a spunbond method, the uniformity of the texture is lacking. In addition, since a special split fiber is used as a raw material fiber and a high-pressure water stream is used to split and perforate the fiber, an increase in cost is inevitable. In addition, in patent document 1, manufacture of the nonwoven fabric by the airlaid method is not disclosed at all.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2004-308938) proposes a water absorbing filter material for a humidifier. In this filter material, a perforated non-woven fabric is prepared on a card web composed of hydrophilic fibers and heat-adhesive fibers by a hydroentanglement method, and a net having an eye larger than the size of the perforated non-woven fabric is adhesively bonded thereto. (Claim 1 etc. of the patent document). This perforated nonwoven fabric has a hole diameter of 1 to 5 mm, a number of holes of 1 to 25 / cm ² , and an opening ratio of 5 to 50% (paragraph “0011” of the same patent document).
Since this filter material has holes, it is said that the air permeability and the air permeability in the thickness direction are good and the shape stability is also good.
However, since the web formation is a carding method, the texture is not uniform, and the pores are formed by a water stream, so that the size and shape of the pores tend to be unstable. In addition, since a high-pressure water stream is used, the cost is high. In addition, Patent Document 2 does not disclose the production of a nonwoven fabric by the airlaid method at all.

Further, in Patent Document 3 (Japanese Patent Publication No. 7-91762), a web made of thermoplastic fibers is heated with a pair of rolls made of an embossing roll and a flat roll having a temperature not higher than the melting point of the thermoplastic fibers. Proposed is a perforated nonwoven fabric that is used for clothing interlining, etc. by pressurizing and punching the web to form through-holes and simultaneously heat-sealing the fibers around the through-holes to each other. Document claim 1 etc.).
This perforated nonwoven fabric can be continuously produced, and various hole patterns are possible.
However, since it is a calendar roll system, it is easy to increase the density and it is difficult to maintain the bulkiness. Moreover, it is necessary to peel off the punching piece adhering to the flat roll. Furthermore, the extracted piece becomes a loss and the basic unit is bad. In addition, Patent Document 3 does not disclose the production of the nonwoven fabric by the airlaid method at all.

Japanese translation of PCT publication No. 2002-527636 JP 2004-308938 A Japanese Patent Publication No. 7-91762

  The present invention provides a perforated nonwoven fabric sheet that can be used as it is in the air-laid nonwoven fabric, does not cause any loss of raw material fibers, and can have a pore size exceeding 1 cm, and is useful for various applications. is there.

The present invention is an airlaid nonwoven fabric mainly composed of heat-adhesive synthetic fibers, having a total basis weight of 15 to 150 g / m ² and having a large number of holes, and the number of holes is 5,000 to 60,000 / It relates to a perforated nonwoven fabric sheet (hereinafter also referred to as “nonwoven fabric sheet”) having a total area ratio of 20 to 70% at m ² .
Here, the constituent component of the non-woven fabric is preferably composed of only heat-bonding synthetic fibers.
Moreover, the said hole is substantially spherical and / or elliptical, and when spherical, the diameter is preferable, and when elliptical, the minor axis or major axis is preferably 1 to 30 mm.
Next, this invention relates to the absorbent article which used the said perforated nonwoven fabric sheet as a structural member.
Next, the present invention conveys a fiber mainly composed of a predetermined amount of defibrated thermoadhesive synthetic fiber while uniformly dispersing it in an air stream, and the fiber blown out from the pores provided in the discharge part, A metal or plastic fiber collecting net installed at the bottom, and a protrusion having a height 1.2 to 5 times the thickness of the laminated fiber web is locally provided on the net. A method for producing the perforated nonwoven fabric sheet, wherein the fiber is deposited on the net while dropping on a net for collecting fibers and suctioning air at the bottom of the net, and the operation is repeated a plurality of times as necessary. .

  Since the perforated nonwoven fabric sheet of the present invention is a perforated nonwoven fabric sheet mainly composed of heat-adhesive synthetic fibers and formed by the airlaid method, loss of raw material fibers does not occur, and (1) High liquid permeability, small contact area with skin, less irritation to skin, less wet feeling due to discharged liquid, less moisture and less stuffiness, (2) Garbage for wipers (3) As a food drip absorbent sheet, because the contact area is small, food is not easily damaged, and the wetback of discharged and absorbed liquid is also small. (4) High It has air permeability, is suitable for various packaging materials and cushioning materials, and (5) has a large surface area and is suitable for adsorption of malodorous gases, and is useful for adsorbent sheets.

Embodiments of the present invention will be described below.
The perforated nonwoven fabric sheet of the present invention is composed of an air-laid nonwoven fabric mainly composed of heat-adhesive synthetic fibers and having a basis weight of 15 to 150 g / m ² .
Here, “main component” means that the heat-adhesive synthetic fiber is 70% by weight or more, preferably 85% by weight or more, and about 30% by weight or less of other fibers and pulp described later. It may be included.
In addition, the nonwoven fabric sheet of the present invention is mainly composed of heat-adhesive synthetic fibers. In addition to those using 100% by weight of the heat-adhesive synthetic fibers, for example, heat-adhesive synthetic fibers + pulp fibers, or heat You may be comprised from the one or more air-laid nonwoven fabric which consists of adhesive synthetic fiber + pulp fiber + chemical binder.
In particular, from the viewpoint of sheet strength, it is preferable that the sheet is composed only of heat-bonding synthetic fibers.

  Here, the heat-adhesive synthetic fiber in the present invention may be anything as long as it is melted by heat and bonded to each other, and the nonwoven fabric itself is fixed in a network structure by the inter-fiber bond. Examples of such heat-adhesive synthetic fibers include polyolefins grafted with polyolefins, unsaturated carboxylic acids, fibers obtained from biodegradable resins such as polyesters, polyvinyl alcohol, and polylactic acid. Can be mentioned.

  As such a heat-bonding synthetic fiber, a core-sheath type or an eccentric side-by-side type composite fiber is suitable. Examples of the low melting point adhesive component constituting the sheath or the outer periphery of the fiber include polyolefins such as polyethylene, polypropylene, and ethylene / propylene copolymers, and low melting point copolymer polyesters. The polymer constituting the core component or the inner fiber layer is preferably a polymer having a melting point higher than that of the sheath and not changing at the heat bonding treatment temperature. As such a combination, for example, the sheath / core may be polyethylene / polypropylene, polyethylene / polyester, polypropylene / polyester, low-melting copolymer polyester / polyester, and the like. These polymers may be modified as long as they do not impair the action / effect of the present invention. Furthermore, it may be a fibrillar fiber. For example, SWP of Mitsui Chemicals, Inc. is mentioned.

  When heat-synthetic synthetic fibers are thin, the number of constituent fibers increases and the fiber spacing decreases, which improves the concealment required for applications such as hygiene materials and food drip absorbers, and also softens the texture and feel. . If it is thick, the gap between the fibers becomes large, and it becomes a bulky nonwoven fabric, and the air permeability is also improved, so that an increase in humidity near the skin is suppressed, and the effect of reducing the feeling of stuffiness can be expected. Therefore, the thickness of the fiber may be selected according to the application, but the preferred fineness is 0.5 dt to 50 dt, and more preferably 0.8 dt to 30 dt. If it exceeds 50 dt, the resulting non-woven sheet becomes hard and unpleasant to the touch or irritation to the skin increases. On the other hand, if it is less than 0.5 dt, the productivity of the nonwoven fabric is lacking, which is not practical.

  The length of the heat-bonding synthetic fiber is preferably 1 to 15 mm. If the fibers are short, the spreadability is improved, and a more uniform nonwoven fabric is likely to be obtained. However, if the fibers are less than 1 mm, they are close to a powder form, making it difficult to form a network structure by bonding between fibers, and the strength as a nonwoven fabric is reduced. It is not preferable because it lacks properties. On the other hand, if the length is longer than 15 mm, the strength of the nonwoven fabric increases, but the fibers tend to get entangled during pneumatic transportation of the fibers during the production of the nonwoven fabric, which increases the fiber lump defects, which is not preferable. Particularly preferred is 3 to 10 mm.

  In addition to the above heat-adhesive synthetic fibers, the nonwoven fabric sheet of the present invention includes regenerated fibers such as rayon, semi-synthetic fibers such as acetate, synthetic fibers such as polyester, polypropylene, polyamide and vinylon, and fibrillar fibers such as SWP. Other fibers such as natural fibers such as pulp, cotton and hemp may be included. In this case, the proportion of the heat-adhesive synthetic fiber in the nonwoven fabric sheet is preferably 70 to 100% by weight, more preferably 85 to 100% by weight. When the amount is less than 70% by weight, there is a high possibility that the other fibers will fall off, and the wet strength may be lowered, which causes a practical problem.

These fibers forming the nonwoven fabric sheet of the present invention are thermally bonded, and the nonwoven fabric sheet is fixed in a network structure by interfiber bonding.
The nonwoven fabric sheet of the present invention has a total basis weight of 15 to 150 g / m ² , preferably 20 to 100 g / m ² . If it is less than 15 g / m ² , the strength of the nonwoven fabric is reduced, and practical problems such as nonwoven fabric manufacturing processability and handling as a product are likely to occur. On the other hand, if it exceeds 150 g / m ² , the sheet becomes stiff and the touch is also deteriorated, resulting in practical problems.

  Such a nonwoven sheet of the present invention is produced by an airlaid method. The nonwoven fabric produced by the airlaid method is preferred because the fibers forming the nonwoven fabric are randomly three-dimensionally oriented in the longitudinal direction, width direction and thickness direction of the nonwoven fabric.

Here, the nonwoven fabric by the airlaid method which concerns on this invention can be obtained as follows.
That is, a fiber mainly composed of a predetermined amount of defibrated thermoadhesive synthetic fiber is conveyed while being uniformly dispersed in an air flow, and the fiber blown out from the pores provided in the discharge unit is installed in the lower part. A metal or plastic fiber collection net having a protrusion locally having a height of 1.2 to 5 times the thickness of the laminated fiber web on the net The fiber is deposited on the net while dropping down and sucking air under the net, and this operation is repeated a plurality of times as necessary.
For example, the second and subsequent web depositions are similarly deposited on the deposition sheet.
Thus, a hole corresponding to the protrusion is formed.
Next, the nonwoven fabric of the present invention can be obtained by heat-treating the whole to a temperature at which this heat-adhesive synthetic fiber sufficiently exhibits its adhesive effect. In order to sufficiently exhibit the adhesive effect, heat treatment at a temperature 5 to 20 ° C. higher than the melting point of the adhesive component of the heat-adhesive synthetic fiber is necessary.

When using a chemical binder resin, spray a chemical binder resin such as hot melt adhesive, latex adhesive, emulsion adhesive, or resin powder adhesive on the deposited web for each web formation. Or it may be applied.
Here, examples of components of these chemical binder resins include polyolefin-based, polyvinyl acetate-based, polyacrylate-based, synthetic rubber-based, polyurethane-based, epoxy-resin-based, and thermosetting resin-based.
The use amount of these chemical binder resins is usually ^{2 to 20} g / m ² , preferably 4 to 10 g / m ² in terms of solid content, and does not cause the bonding of synthetic fibers or pulp fibers or peeling of each layer. It is decided by.

  Moreover, functional processing, such as deodorizing, antibacterial, aroma, moisture retention, coloring, hydrophilicity, and water repellency, can be imparted to the nonwoven fabric sheet of the present invention. Examples of the processing method include a method in which fibers having these functions are mixed in advance, a powdery agent is mixed, and a liquid agent is sprayed or impregnated.

  Thus, the nonwoven fabric manufactured by the airlaid method can three-dimensionally orient the fibers at random in the flow direction, width direction and thickness direction of the nonwoven fabric. And since these are thermally bonded, delamination does not occur. Moreover, since the non-woven fabric produced by the airlaid method has good uniformity, there is less variation in performance.

Here, as the fiber collection net used in the present invention, as shown in FIGS. 1 and 2, on a normal plastic or metal collection net, a constant interval (for example, for collection). A = 7 mm in the longitudinal direction of the net and b = 10 mm in the lateral direction), for example, ultraviolet curable resin is printed by screen printing or applied, and then the resin is cured by irradiating with ultraviolet rays, A protrusion having a synthetic resin mass (for example, width w = 3 mm, length 1 = 5 mm, height h = 2.2 mm) is formed.
Here, the height h of the synthetic resin lump is 1.2 to 5 times, more preferably 1.3 to 3.5 times the thickness t of the fiber web laminated on the collection net. If the height h of the synthetic resin mass is less than 1.2 times the thickness t of the fiber web to be laminated, the holes corresponding to the synthetic resin mass may not be formed. It is too high and lacks stability and cannot withstand continuous production.
Specific examples of the synthetic resin block include a spherical or elliptical shape having a diameter (short axis or long axis) of 1 to 30 mm and a height of about 1 to 10 mm.
As described above, the synthetic resin block may be formed in a substantially spherical shape in addition to the elliptical shape shown in FIG. In addition, the synthetic resin lump may be oval and substantially spherical.
Moreover, as a specific example of the substantially elliptical size shown in FIG. 2, a is 3 to 40 mm, b is 2 to 30 mm, width w is 1 to 20 mm, length l is 1.5 to 30 mm, and height h is The thing of 1-10 mm is mentioned.

In addition, formation of a synthetic resin lump is not limited to the above means, but olefin resin such as polyethylene and polypropylene, polyester elastomer resin, nylon resin, thermoplastic or curable polyurethane resin, epoxy resin Alternatively, in a molten state or a liquid state in which a curing agent is mixed, the rubber-based resin may be directly discharged to a predetermined position on the collection net to be cooled and solidified or heat-cured. Slurry synthetic resins such as polyvinyl chloride resins can also be used. Furthermore, a foaming agent may be mixed in advance to form a foam.
Since it is necessary to apply a temperature 5 to 20 ° C. higher than the melting point of the adhesive component of the heat-bonding synthetic fiber in the heat treatment for imparting the inter-fiber bond of the airlaid web, the resin forming these synthetic resin lumps is at this temperature. The one with higher heat resistance temperature is required. The heat-resistant temperature is 140 ° C. or higher, preferably 160 ° C. or higher.

The magnitude | size of the above protrusion (equivalent to the hole of a perforated nonwoven fabric sheet) is suitably set by the magnitude | size corresponding to the hole of the nonwoven fabric sheet obtained. Here, the nonwoven fabric sheet of the present invention is obtained by heat-treating the entire fiber web at a temperature 5 to 20 ° C. higher than the melting point of the adhesive component of the thermoadhesive synthetic fiber. Since heat shrinkage often occurs, the holes tend to be slightly smaller by heat treatment. Therefore, in order to obtain the desired depth and size of the hole, it is preferable to set the height and size of the synthetic resin mass (projection) to be formed on the collection net to be slightly larger in advance. For example, the ratio of the size of the hole and the size of the synthetic resin block (projection) is preferably in the range of 1 / 1.05 to 1.5. This differs depending on the thermal characteristics of the heat-adhesive synthetic fiber used, the heat treatment method, and the conditions.
In addition, the shape of the protrusions such as a synthetic resin block is almost spherical or elliptical, and it represents triangles, squares, polygons, crosses, straight lines, curves, lattices, meshes, irregular shapes, or letters, some marks, logos. There may be.

When a fiber web is deposited by the airlaid method using a fiber collection net having such protrusions, for example, as shown in FIG. 1, the synthetic resin lump part is non-permeable to air flow. The fiber web flows on the permeable net side to obtain a porous fiber web in which holes corresponding to the protrusions of the synthetic resin block are formed.
Furthermore, for example, if the above-described fiber web having one or two layers is formed thereon, a two-layer or three-layer porous fiber web can be obtained.
And as FIG. 1 shows, since the height h of the synthetic resin lump is 1.2 times or more than the thickness t of the fiber web laminated | stacked on the collection net | network, it respond | corresponds to a synthetic resin lump. A fiber web is not laminated | stacked on a location, but a hole is each formed in the location corresponding to this synthetic resin lump.

Next, this fiber web is heat-treated as a whole at a temperature 5 to 20 ° C. higher than the melting point of the adhesive component of the heat-bonding synthetic fiber, whereby the perforated nonwoven fabric sheet of the present invention can be obtained.
A specific example of this heat treatment is hot air treatment. For example, the hot air treatment for forming the fiber-to-fiber bond includes a melting point higher than the melting point of the low melting point component of the thermoadhesive conjugate fiber (the sheath component of the core-sheath type conjugate fiber or the low melting point component of the side-by-side type conjugate fiber). Temperature is needed. However, if the melting point is 30 ° C. or higher than the melting point of the low melting point component, or the melting point of the high melting point component (the core component of the core-sheath type composite fiber or the high melting point component of the side-by-side type composite fiber), the heat shrinkage of the fiber. Is not preferable because it tends to be large and deteriorates the texture. Accordingly, the hot air treatment temperature is usually 110 to 200 ° C, preferably 120 to 180 ° C.

The perforated nonwoven fabric sheet of the present invention obtained as described above has a hole (corresponding to the projection of the synthetic resin lump) and a laminated web part (web deposited on a portion where the synthetic resin lump is not formed). Is done. That is, in the perforated nonwoven fabric sheet of the present invention, a plurality of holes are formed on the laminated web.
Here, the number of holes is 5,000 to 60,000 holes / m ² , preferably 8,000 to 50,000 holes / m ² . If the number of holes is less than 5,000 / m ² , it means that small holes are scattered sparsely or the size of the holes is extremely large. When the small holes are sparse, the action and effect of the present invention are reduced. On the other hand, when the holes are too large, a liquid reversal phenomenon occurs when used in an absorbent article. On the other hand, when it exceeds 60,000 pieces / m ² , it means that the size of the hole is too small or the interval between the holes is too small. When the hole is too small, not only the action and effect are diminished, but also a very small resin lump projection is produced on the collection net, so that it cannot be produced with high accuracy and is not realistic. When the interval between the holes is narrowed, the sheet strength is lowered, so that it cannot be practically used.
The number of holes can be appropriately set depending on the number of the synthetic resin blocks per unit area on the collection net.

Moreover, the total area ratio of the holes on the perforated nonwoven fabric sheet of the present invention is 20 to 70%, preferably 30 to 60%. If it is less than 20%, it is difficult to obtain the performance characteristics obtained by the holes. On the other hand, if it exceeds 70%, the holes are too close to each other and the sheet strength is lowered, which is not practical.
In order to set the total area ratio of the holes within this numerical range, the resin block design should be optimized. For example, the total area ratio of the holes can be appropriately set according to the size of the synthetic resin block in the planar direction, the dimensions of the intervals a and b shown in FIG.

  When the perforated nonwoven fabric sheet of the present invention is used for a top sheet of an absorbent article, the liquid transfer to the absorbent is smooth through the hole and the contact area with the skin is small, so the skin irritation is small. , The wet feeling due to the discharged liquid is small, and there is an excellent effect that the stuffiness is reduced. Even when used between the top sheet and the absorbent body, that is, as a second sheet, an effect close to the above can be expected.

For example, as shown in FIG. 1, the perforated nonwoven fabric sheet of the present invention has a plurality of holes corresponding to a synthetic resin lump, and the size of the holes is a spherical diameter or an elliptical short diameter. Alternatively, the major axis is 1 to 30 mm, preferably 1.5 to 25 mm, and the depth (corresponding to the thickness t of the fiber web) is 0.2 to 5 mm, preferably 0.3 to 4 mm. When the diameter (or short diameter or diameter) of the hole is less than 1 mm, the effect obtained by the hole is small. On the other hand, when the diameter exceeds 30 mm, the sheet strength is reduced, which is not practical. In addition, if the depth of the hole (corresponding to the thickness of the fiber web) is less than 0.3 mm, the effect obtained by the hole is also small, whereas if the depth (thickness) exceeds 5 mm, it contacts the human body. Not only is it unusable and practical in the use of sanitary materials, wipers, and absorbers, but when such a high resin lump is applied to a collection net, it tends to collapse or tilt in continuous production. So it causes production problems.
The size of the hole can be easily adjusted by changing the size of the synthetic resin lump (projection) or changing the heat treatment condition of the fiber web.

In addition, the nonwoven fabric sheet of the present invention may have some fiber webs in the holes as long as it is within the scope of the present invention. In this case, the basis weight of the fiber webs in the holes is 6 g / m ^2. Less than an amount may be present.
Moreover, the perforated nonwoven fabric sheet of this invention does not need to exist in the sheet | seat whole surface, if the zone in which many holes exist is 20 to 70% of the sheet | seat whole surface. For example, a zone having a large number of holes and a zone having no holes at the same time may coexist in alternate stripes such as vertical, horizontal, and diagonal, or a zone having a large number of holes may be circular. Alternatively, it may be a pattern such as a square.
Furthermore, as long as it is within the scope of the present invention, the hole may not have a fixed shape, and may represent a character or some pattern or logo.

Thus, the perforated nonwoven fabric sheet of the present invention has a three-dimensional structure in which a plurality of holes are formed on the nonwoven fabric sheet, and is useful as a surface sheet or a second sheet of an absorbent article.
The sheet of the present invention is used for sanitary products, sanitary napkins, cage sheets, paper diapers, etc., as well as drip absorbers for food trays that absorb liquids such as moisture and blood generated from food, or humans, objectives, etc. It is also suitable for a dry or wet wiper.
The perforated nonwoven fabric sheet of the present invention has holes such as a honeycomb shape and a lattice shape, and is also used as various packaging materials and cushioning materials having high air permeability.
Moreover, since the porous nonwoven fabric sheet of the present invention has a large surface area, by containing an adsorbent fiber such as fibrous activated carbon, activated carbon, adsorbent powder such as silica gel, etc. in the fiber web, malodorous gas, It is also used as an adsorbent sheet for malodorous liquids and moisture.

  In addition, the porous nonwoven fabric sheet of this invention can also be hot-pressed following said hot air process. A calendering process is used for the hot-pressing process as needed. It is preferable to calender after the shape of the nonwoven fabric of the hole and the fiber web is stabilized by hot air treatment. As a roller used for the calendering treatment, it is preferable to use a pair of metal rollers having a smooth surface or a combination of a metal roller and an elastic roller in order to apply a uniform heat pressure to the whole, but a multi-stage roller may also be used. In addition, an embossing roller with an uneven surface may be used as long as the gist of the present invention is not impaired.

  The temperature at the time of calendering is appropriately selected depending on the type of heat-adhesive conjugate fiber used and the overall weight, but if hot air treatment has been carried out in advance, the hot-pressure treatment serves as a thickness adjustment function. It can be arbitrarily set within the range up to the melting point of the low melting point component. In the case of a high temperature close to the melting point, the strength of the nonwoven fabric tends to increase. When it is close to normal temperature, it can be adjusted to an appropriate thickness required as a product while maintaining the performance as a perforated nonwoven fabric sheet. Preferably, it is normal temperature-100 degreeC.

  Moreover, if the linear pressure of a calendar process is set so that it may become a uniform linear pressure in the width direction, arbitrary pressures can be selected. When the pressure is too high, there are disadvantages due to the flattening and densification of the fibers as in the above-described high temperature calendar treatment, and when the pressure is too low, the effect of adjusting the thickness is low. Usually, 2 to 30 kgf / cm is preferable.

  Further, the perforated nonwoven fabric sheet of the present invention is a composite of an airlaid nonwoven fabric and another nonwoven fabric, for example, thermal bond, spunlace, chemical bond, spunbond, melt blown, wet nonwoven fabric, plastic net, woven or knitted fabric, cold koji, wrinkle, etc. It may be. As a means for compounding, a method that does not impair the gist of the present invention, such as hot melt, chemical bond, powder bond, calender, dod embossing, etc. may be selected as appropriate, but most preferably, a carrier sheet at the time of airlaid web collection And a method of laminating and integrating.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1 (for hygiene)
In FIG. 2, a commercially available two-component mixed type is used in a PET (polyethylene terephthalate) collection net so that a = 7 mm, b = 10 mm, w = 3 mm, l = 5 mm, and h = 2.2 mm. A large number of dot-shaped resin lumps were formed using an epoxy resin (manufactured by Konishi Co., Ltd., Bond Quick 5 # 16123). On top of this, a web was formed by an airlaid method so that a heat-adhesive conjugate fiber made of sheath PE (polyethylene) / core PET (manufactured by Teijin Fibers Ltd., 2.2 dt × 5 mm) was 12 g / m ² . Further, a sheath PE / core PET heat-adhesive conjugate fiber (manufactured by Teijin Fibers Limited, 1.7 dt × 5 mm) was further formed thereon by an airlaid method so as to be 12 g / m ² . The 24 g / m ² airlaid bilayer web was then heated in a heat oven to 145 ° C. to produce interfiber bonding to produce a perforated nonwoven sheet. The number of holes was 28,500 holes / m ² , the sheet thickness measured at the non-perforated portion was 0.4 mm, and the total area ratio of the holes was 34%.
After removing the surface sheet of a commercially available sanitary product and replacing it so that the non-net surface of this sheet is in contact with the skin, menstrual blood is quickly transferred from the perforated part to the absorber, and is difficult to reverse. there were. Since the surface sheet has voids, the skin feels smooth and feels good, and the sheet is useful as a sanitary material.

Comparative Example 1 (for hygiene applications)
A net without a resin lump was used as a collection net, and everything else was the same as in Example 1 to obtain a 24 g / m ² airlaid nonwoven sheet without holes. The sheet thickness was 0.35 mm.
When this was used as a surface sheet of a sanitary product in the same manner as in Example 1, the absorption speed of menstrual blood was somewhat slow because there were no holes, and the entire surface of the sheet was in contact with the skin, and there was a feeling of stuffiness. It was lacking in comfort.

Example 2 (for hygiene applications)
After peeling off the surface sheet of a commercially available sanitary product, the sheet of Example 1 was sandwiched between the surface sheet and the absorbent body and used as a second sheet. The initial absorption rate of menstrual blood is not deteriorated, it is practically sufficient, and there is almost no reversal of menstrual blood from the absorbent body, the smooth feeling of the skin is good, and the sheet is useful as a sanitary material. It was.

Comparative Example 2 (for hygiene applications)
The holeless sheet of Comparative Example 1 was used as a second sheet in the same manner as in Example 2. Since there were no pores, the absorption rate was slow, the skin was moist, and the comfort was lacking.

Example 3 (for cleaning purposes)
In FIG. 2, in the same manner as in Example 1, a dot-shaped resin was used on a PET collection net so that a = 13 mm, b = 15 mm, w = 6 mm, l = 10 mm, and h = 2.7 mm. Many lumps were formed. On top of this, a web was formed by an air laid method so that a heat-adhesive conjugate fiber made of sheath PE / core PET (manufactured by Teijin Fibers Ltd., 2.2 dt × 5 mm) was 50 g / m ² . Subsequently, it heated to 145 degreeC in the heat oven, the bond between fibers was produced, and the perforated nonwoven fabric sheet was created. The number of holes was 10,250 / m ² , the sheet thickness measured at the non-perforated portion was 0.7 mm, and the total area ratio of the holes was 48%.
This perforated nonwoven fabric sheet was cut into a length of 200 mm × width of 300 mm, and attached to a commercially available floor cleaning tool with a stick, and used as a household flooring sheet. Since it has a hole, it is easy to capture and maintain human, small animal hair, textile waste, dust, etc., and it was useful as a cleaning sheet.

Example 4 (food drip absorber)
A large number of dot-shaped resin lumps were formed on a PET collection net so as to have the same shape as in Example 3.
On top of this, 10 g / m ^{2 of} a heat-adhesive conjugate fiber made of sheath PE / core PET (manufactured by Teijin Fibers Ltd., 2.2 dt × 5 mm), and then heat-bonded sheath PE / core PP 70 g / m ^{2 of} an 80/ ²⁰ % by weight mixture of a functional composite fiber (manufactured by Chisso Polypro Fiber Co., Ltd., 1.7 dt × 5 mm) and a pulverized product of wood pulp (manufactured by Weyerhaeuser, NB416) Heat-adhesive conjugate fibers made of sheath PE / core PET (manufactured by Teijin Fibers Ltd., 2.2 dt × 5 mm) were each formed at 10 g / m ² by the airlaid method. Next, this air-laid three-layer laminated web having a total of 90 g / m ² was heated to 145 ° C. in a heat oven to cause interfiber bonding, thereby preparing a porous nonwoven fabric sheet. The number of holes was 10,250 / m ² , the thickness of the non-perforated part was 1.2 mm, and the total area ratio of the holes was 48%.
The sheet cut to 15 cm × 20 cm was placed on a styrene foam tray, and 300 g of fresh bonito fillet was stored. The whole was wrapped in a wrap and allowed to stand at room temperature for one day. The drip solution from bonito was all retained in this sheet, and there was no accumulation at the bottom of the tray, and the contact area of the sheet was small, so there was little damage to the fish meat and it was useful as a drip absorbent sheet for food. .

  The perforated nonwoven fabric sheet of the present invention is useful as a surface sheet or a second sheet used for sanitary products, sanitary napkins, cage sheets, disposable diapers and other absorbent articles. In addition, the perforated nonwoven sheet of the present invention is a drip absorbent for food trays that absorbs liquids such as blood and moisture generated from food, food packaging sheets, cushioning materials, or dry forms used for people, objectives, etc. Or a wet wiper, and furthermore, because it has a large surface area, it is suitable for adsorption of malodorous gases and the like and can be used for an adsorbent sheet.

In the manufacturing process of the perforated nonwoven fabric sheet of this invention, it is explanatory drawing which shows the fiber web deposited on the net for collection. It is a plane lineblock diagram of a collection net used for manufacture of a perforated nonwoven fabric sheet of the present invention.

Claims (5)

A fiber mainly composed of a predetermined amount of defibrated thermoadhesive synthetic fiber is conveyed while being uniformly dispersed in an air stream, and the fiber blown out from the pores provided in the discharge section is made of metal or A plastic fiber collection net on a fiber collection net provided locally with protrusions having a height of 1.2 to 5 times the thickness of the laminated fiber web While dropping and sucking air at the bottom of the net, the fiber is deposited on the net, and if necessary, this operation is repeated a plurality of times. 15-150 g / m ² An airlaid nonwoven fabric having a large number of holes, the number of holes being 5,000 to 60,000 / m ² A perforated nonwoven fabric sheet having a total area ratio of holes of 20 to 70%.   The perforated nonwoven fabric sheet according to claim 1, wherein the constituent component of the nonwoven fabric consists only of heat-adhesive synthetic fibers. The perforated nonwoven fabric sheet according to claim 1 or 2, wherein the pores are spherical and / or elliptical, the diameter is spherical and the minor axis or major axis is 1 to 30 mm when elliptical.   The absorptive article which used the perforated nonwoven fabric sheet in any one of Claims 1-3 as a structural member. A fiber mainly composed of a predetermined amount of defibrated thermoadhesive synthetic fiber is conveyed while being uniformly dispersed in an air stream, and the fiber blown out from the pores provided in the discharge section is made of metal or A plastic fiber collection net on a fiber collection net provided locally with protrusions having a height of 1.2 to 5 times the thickness of the laminated fiber web The fiber is deposited on the net while dropping and sucking air at the lower part of the net, and if necessary, this operation is repeated a plurality of times, so that the heat-bonding synthetic fiber is the main component, and the overall basis weight is 15 Air-laid nonwoven fabric having a large number of holes, up to 150 g / m ² , the number of holes being 5,000-60,000 / m ² , and the total area ratio of the holes being 20-70 % Made of perforated nonwoven sheet, characterized by Method.

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