JPH1112909A - Water-disaggregative nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject nonwoven fabric having a strength to with stand operations such as cleaning in a dry state and in a wet state, capable of being disaggregated in a large amount of a water flow, by mixing a regenerated cellulose fiber with a wood pulp, forming a web by a wet paper making method and subjecting the web to a high-pressure water jet flow treatment. SOLUTION: A regenerated cellulose fiber in an amount of 15-55 wt.% is mixed with 85-45 wt.% of a wood pulp and subjected to a high-pressure jet flow treatment to give the objective nonwoven fabric in which a readily water- disaggregative ragion to be disaggregated into a fibrous state when a nonwoven fabric of 5 cm×5 cm (25 cm<2> ) size is thrown into 100 mL of pure water, shaken at 300 cycles/minute shaking rate and desegregated in water and a semi-water- disaggregative region relatively hardly water-disaggregative in comparison with the readily water-disaggregative region are distributed throughout the whole nonwoven fabric and the ratio of the readily water-disaggregative region in the nonwoven fabric is 15-70 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-disintegratable nonwoven fabric, which has a strength capable of withstanding a cleaning operation in a dry state and a wet state, and in which a fiber constituting the nonwoven fabric can be disintegrated in a large amount of water flow. The present invention relates to a nonwoven fabric.
More specifically, the present invention is a water-disintegratable nonwoven fabric in which regenerated cellulose fibers and wood pulp are entangled and integrated, and is used as a wet tissue, a cloth, a cleaning wiper and the like as well as in a dry state. Therefore, when it is wet with water or chemicals, or when it is used as a top sheet for disposable diapers or sanitary napkins, it retains the strength that can withstand practical use, and when using a large amount of water flow like a flush toilet, The present invention relates to a water-disintegratable nonwoven fabric that is easily disintegrated or disintegrated by a water flow.

[0002]

2. Description of the Related Art In general, many wet products such as wet tissues, baby wipes and cleaning wipers, and many sanitary articles such as disposable diaper sanitary napkins are discarded as garbage after use. For example, when considering the use of baby wipes or nursing care wipes, wet wipers have superior stool wiping properties, hygiene properties, and low skin irritation, as compared to toilet paper. ing. However, since the wet wiper is composed of a non-woven fabric made of synthetic fiber, the sheet-like shape does not easily collapse with a large amount of water, and it may be treated by flowing into a flush toilet after use due to a flow path blockage trouble. There was a drawback that the waste treatment could be unsanitary because of the failure.

[0003] For this reason, generally used wipes are used only for very limited applications such as baby wipes and nursing wipes for nursing care, and are not widely used in place of toilet paper. Not reached. As a method of improving the wiping property and skin irritation of toilet paper, a method of impregnating a toilet paper with a humectant or the like has been proposed, but it has not reached performance comparable to that of using a wet wiper. Was. Examples of the water-disintegrable paper or nonwoven fabric that can be used as a top sheet of a wet tissue or a sanitary article include, for example, JP-A-47-9486 and JP-A-1-168999.
JP, JP-A-2-149237, JP-A-3-2
No. 77335, Japanese Unexamined Patent Publication No. 4-370300, etc. have been proposed.

JP-A-47-9486 discloses that a binder solution containing polyvinyl alcohol and borax is sprayed on a sheet and then heated and dried, whereby the polyvinyl alcohol and borax react to temporarily react with water. And hydrolyzed paper useful as an absorbent pad for napkins, diapers and the like is disclosed. However, this water-disintegrated paper is not suitable for the use of towels when impregnated with water, and does not have the strength to withstand mechanical cleaning work such as a cleaning sheet for toilets. JP-A-1-16899
No. 9 proposes the use of a calcium salt of water-insoluble carboxymethylated pulp for the base paper. However, in the proposed water-disintegrable paper, the upper limit of the water content in the cleaning liquid is 60%, and therefore it is necessary to add at least 30% of an organic solvent such as alcohol. The applications in which the compounded impregnating liquid can be used are limited, and it is difficult to use it especially for applications such as wiping the ass. Also, by adding an organic solvent, it is necessary to add a large amount of fragrance to eliminate the organic solvent odor,
There is a disadvantage that the strength may be reduced during the cleaning operation due to an increase in the water content due to volatilization of the organic solvent.
Furthermore, the adverse effect on the human body due to the high concentration of the organic solvent cannot be ignored.

Japanese Patent Application Laid-Open No. 2-149237 discloses that a water-disintegrated paper containing a specific water-soluble binder contains an aqueous solution containing a specific metal ion and an organic solvent.
There is disclosed a method for producing a water-disintegratable cleaning article having sufficient strength to perform a cleaning operation in a state of being impregnated with a water-containing cleaning agent, and having a water-disintegrating property that can be easily washed away in a flush toilet. However, this cleaning article
It is necessary to contain a specific metal ion and an organic solvent in the impregnating liquid to be impregnated into the hydrolyzed paper, and the impregnating liquid cannot be freely selected according to the purpose, so its use is extremely limited. I will. Further, as a water-soluble binder having a specific carboxyl group, carboxymethyl cellulose, carboxyethyl cellulose, polysaccharide derivatives such as alkali metal salts such as carboxymethylated starch,
Synthetic polymers, natural products, and the like are mentioned, but the addition of such a water-soluble binder has the disadvantage that the texture of the sheet becomes hard.

Japanese Unexamined Patent Publication (Kokai) No. 3-277335 discloses that water-soluble calcium carboxymethylcellulose is used as a paper-strength enhancer for a base paper and that calcium ions coexist in the cleaning solution, so that it is sufficient even in a cleaning solution having a high water content. A wiping material that exhibits excellent strength and easily disperses in water at 100% water is disclosed. Calcium chloride, calcium acetate, etc. are used as the calcium ion source. The water content of the impregnating solution used is also 8
There is a drawback that about 5% is the upper limit. Today, it goes without saying that a substrate that can be used even if the moisture content in the impregnating liquid is even higher is desirable as the wiping material from the viewpoint of diversification of uses.

Japanese Patent Application Laid-Open No. Hei 4-370300 discloses a multi-layer structure having at least two layers.
Disintegrated paper is disclosed in which one outermost layer contains 10 to 60% of the paper strength agent and the other outermost layer contains 5% by weight or less of the paper strength agent. As the paper strength enhancer used in the outermost layer of the hydrolyzed paper, carboxymethylated pulp salt, water-soluble polyvinyl alcohol, water-soluble polyvinyl alcohol fiber, or a mixture thereof is used. This multi-layered water-disintegrated paper is intended to improve the productivity by reducing the deterioration of the releasability in the dryer part during paper making by adding a paper strength enhancer. However, when there is much moisture in the chemical solution to be impregnated, it is difficult to have sufficient wet strength to withstand use, and a large amount of paper strength enhancer is compounded in the outermost layer on one side of the hydrolyzed paper. There is a drawback that it becomes hard.

In view of the above-mentioned drawbacks of hydrolyzed paper, the present inventors have developed a water-disintegratable nonwoven fabric which is free of binder and has both sufficient strength at the time of use and easy water disintegration after use. A manufacturing method was proposed (Japanese Patent Application No. 8-14 / 1996).
No. 2825). This nonwoven fabric is subjected to a high-pressure water jet flow on a web obtained by mixing a regenerated cellulose fiber having a specific fiber length of 40 to 85% by weight with a pulp fiber having a specific freeness of 15 to 60% by weight and performing wet papermaking. By doing so, fiber entanglement is imparted, and both excellent wet strength and water dissolvability are achieved. However, since the water-disintegratable nonwoven fabric has a high product cost due to the high content of regenerated cellulose fibers such as rayon fibers of 40 to 85% by weight, a water-disintegratable nonwoven fabric that can be produced at lower cost is desired. ing.

[0009]

In view of the above situation, the present inventors have found that even if the content of regenerated cellulose is small, the regenerated cellulose has a strength that can be used in a wet state, and can easily be used in a large amount of water flow. As a result of earnestly examining a method for inexpensively producing a disintegratable nonwoven fabric whose shape disappears, a region where the fibrous material is quickly disintegrated when put into a water stream, it is relatively difficult to disintegrate into a fibrous shape as compared to this region. By distributing the area throughout the nonwoven fabric, even if the wood pulp is blended at a high rate, it shows strength enough to withstand use for cleaning in the wet state and extremely excellent water disintegration in a large amount of water flow, Thus, the present inventors have found that it is possible to achieve both wet strength and water disintegration while significantly reducing the amount of expensive regenerated cellulose fiber used and reducing product cost, and have completed the present invention. An object of the present invention is to reduce the content of expensive regenerated cellulose fibers, to maintain a strength that can withstand operations such as cleaning in dry and wet states, and to constitute a nonwoven fabric in a large amount of water flow. To provide a water-disintegratable nonwoven fabric that can be easily disaggregated.

[0010]

A first aspect of the present invention is a water-disintegrable nonwoven fabric in which regenerated cellulose fibers and wood pulp are entangled and integrated with each other.
55% by weight and 85-45% by weight of wood pulp,
5 cm x 5 cm (25 cm ² ) of the nonwoven fabric
When put into 00 ml of pure water and shaken at a shaking speed of 300 cycles / min and disintegrated in water, the easily disintegrable region that disintegrates in a fibrous form is relatively compared with the easily disintegratable region. The quasi-water-disintegrable regions that are difficult to disintegrate in a fibrous form are distributed over the entire nonwoven fabric, and the proportion of the easily water-disintegrable region in the nonwoven fabric is in the water-disintegratable nonwoven fabric of 15% to 70%.

A second aspect of the present invention is that in the water-disintegratable nonwoven fabric, the quasi-water-disintegrable region is surrounded by the easily water-disintegrable region, and the area per one of the quasi-water-disintegrable regions is 0.2 cm ^2.
It is present in a water-disintegrable non-woven fabric of about ² cm ² .

The third aspect of the present invention is to provide a water-disintegratable nonwoven fabric as described in the first or second aspect, wherein a regenerated cellulose fiber (15 to 55% by weight) and wood pulp (85 to 45% by weight) are mixed and wet-papermaking is performed. A method for producing a water-disintegratable nonwoven fabric in which a formed web is subjected to a high-pressure water jet flow treatment on a perforated support to entangle and integrate regenerated cellulose fibers and wood pulp, wherein a web and a high-pressure water jet flow generator are interposed. A high-pressure water jet flow shielding plate is installed on the high-pressure water jet flow shielding plate, and the high-pressure water jet flow shielding plate is applied to the web by the high-pressure water jet flow. A non-opening that can block all or part of the energy to be applied before the jet stream reaches the web, and an aperture that can directly apply the web without blocking any energy. In which Zonzuru the method of producing a water-decomposable non-woven fabric.

A fourth aspect of the present invention is that, in the water-disintegratable nonwoven fabric described in the first aspect, an easily water-disintegrable region that disintegrates in a fibrous form when disintegrated in water and a quasi-water-disintegrable region that is difficult to disintegrate in a fibrous state alternately. The water-disintegratable nonwoven fabric is distributed in a strip shape over the entire nonwoven fabric, and the proportion of the easily water-disintegrable region in the nonwoven fabric is 15 to 60%.

A fifth aspect of the present invention resides in the water-disintegratable nonwoven fabric described in the fourth aspect, wherein the width of the water-disintegrable region is 3 to 15 mm.

A sixth aspect of the present invention is that, in the water-disintegrable nonwoven fabric described in the fourth to fifth aspects, a regenerated cellulose fiber of 15 to 55% by weight and a wood pulp of 85 to 45% by weight are mixed and subjected to wet papermaking. In a method for producing a water-disintegratable nonwoven fabric in which a formed web is subjected to a high-pressure water jet flow treatment on a perforated support to entangle and integrate regenerated cellulose fibers and wood pulp, two types of high-pressure water jets having different nozzle hole arrangements are provided. The present invention resides in a method for producing a water-disintegratable nonwoven fabric in which a high-pressure water jet flow treatment is performed by combining at least one row with a flow generator so as to be parallel to the width direction of the web.

A seventh aspect of the present invention is the water-disintegrable nonwoven fabric described in the fourth to fifth aspects, wherein one of the high-pressure water jet flow generators has pores at regular intervals over a width of 3 to 20 mm in the width direction of the web. Perforated area and 3 to 15 mm in the web width direction
Non-perforated area having no pores over the entire width direction of the web has a partially perforated nozzle alternately arranged, and a high-pressure water jet flow area and no high-pressure water jet flow are treated. A high-pressure water jet stream generator capable of generating regions alternately in the web width direction, and the other of the high-pressure water jet stream generators has a fully open nozzle in which pores are arranged at regular intervals over the web width direction. The present invention relates to a method for producing a water-disintegratable nonwoven fabric, which is a high-pressure water jet flow generator capable of uniformly performing a high-pressure water jet flow treatment over the entire web width direction.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The most important point of the present invention is that the easily disintegratable region in which water can easily disintegrate into a fibrous form in a water stream and the disintegration in fibrous state relatively quickly compared to the easily disintegratable region. It is difficult to distribute the quasi-water-disintegrable region having excellent strength over the entire nonwoven fabric. Generally, when a water-disintegratable nonwoven fabric is put into a large amount of water and disintegrated, the water-disintegratable nonwoven first disintegrates into several small pieces due to the shear force of the water flow. Furthermore, while the small pieces are finely divided by the water flow, they eventually disintegrate into fibrous shapes. The water-disintegratable nonwoven fabric according to the present invention has a water-disintegrable region that can be quickly disintegrated into a fibrous form in a water stream, and a fibrous disintegration that is relatively quick compared to the water-disintegrable region, but has excellent strength. By distributing the water-disintegrable region and the entire nonwoven fabric, when the water-disintegratable nonwoven fabric is put into a large amount of water, first, the easily water-disintegrable region quickly disintegrates into a fibrous form and is divided into small pieces composed of a quasi-water-disintegrable region. As a result, a sheet excellent in water disintegration is obtained.

The water-disintegrable nonwoven fabric according to the present invention will be described in detail by showing an example of a method for producing the water-disintegrable nonwoven fabric. First, a web is prepared by forming a web from a raw material composed of regenerated cellulose fiber and wood pulp by a wet papermaking method using a known paper machine, and then a high-pressure water jet stream is injected from the surface of the web to form a known water stream. The fibers of the regenerated cellulose and wood pulp are entangled by the entanglement method. In the present invention, the water-disintegratable nonwoven fabric is a nonwoven fabric that has a sheet-like form in a dry and wet state, but can be disintegrated into a fibrous form very quickly by breaking or collapsing a large amount of water flow. Say.

The regenerated cellulose fiber used in the present invention is a viscose rayon in which cellulose such as wood chemical pulp or cotton linter is made into a solution in the form of viscose, and the cellulose is regenerated and spun in an acid. Copper ammonia rayon regenerated and spun in acid after dissolving in ammonia solution, N-methylmorpholine-N
-Regenerated cellulose fibers obtained by dissolving cellulose in a non-aqueous cellulose solvent such as oxide and then spinning. The fineness of the regenerated cellulose fiber is in the range of 1.0 to 5.0 denier. If the fineness is less than 1.0 denier, dispersion becomes difficult during wet papermaking, and a wet web with good texture cannot be obtained. In addition, regenerated cellulose fibers having a fineness of less than 1.0 denier are difficult to manufacture stably, so they are difficult to obtain at a low price, and the rigidity of the fibers themselves tends to be low. This is not suitable because the nonwoven fabric has poor water dissolvability as a result.

Conversely, the regenerated cellulose fiber has a fineness of 5.0.
The water-disintegratable non-woven fabric obtained after denier becomes hard,
The texture and feel will be inferior. When the diameter of the regenerated cellulose fiber used is D and the length is L, the ratio of the diameter to the length, L / D, is in the range of 250 to 900.
If the L / D of the fiber is less than 250, the flexibility of the fiber is insufficient, and sufficient fiber entanglement can be obtained even when the web entangled by jetting a web high-pressure water jet containing such regenerated cellulose fibers. And the wet strength of the resulting water-disintegratable nonwoven fabric is poor. On the other hand, if the L / D of the regenerated cellulose fiber exceeds 900, it is difficult to uniformly disperse the fiber during wet papermaking, so that not only a well-formed web cannot be obtained, but also a strong fiber by high-pressure water jet flow treatment. Since confounding occurs, the non-woven fabric has extremely poor water dissolvability and is not suitable.

On the other hand, wood pulp used by mixing with the regenerated cellulose fiber has a Canadian standard freeness of 550 m.
Any wood chemical pulp of lCSF or higher can be used. For example, for wood pulp, unbleached chemical pulp obtained by digesting softwood or hardwood by the kraft method, the soda method, the polysulfite method, or the like, and further, the unbleached chemical pulp is bleached with a Hunter brightness of 70 to 90%.
Bleached chemical pulp or the like can be used alone or in combination.

The freeness of the pulp is JIS P 81
In the present invention, those having a Canadian standard freeness shown in No. 21 and 550 ml CSF or more are used. The freeness is 550m
When it is less than 1CSF, when used as a nonwoven fabric by mixing with the regenerated cellulose fiber, the content of the regenerated cellulose fiber which relatively inhibits the bonding strength in the present invention is small, so that the bonding force between the pulp fibers becomes too strong. Although this contributes to increasing the wet strength of the obtained nonwoven fabric, it is not suitable because the water disintegration of the nonwoven fabric is significantly deteriorated.

The freeness of pulp has the highest value when pulp is used without being beaten, and this value depends on the species, tree species,
Although it varies widely over a wide range due to digestion, bleaching, etc., the freeness of wood pulp that has not been beaten (the pulp is not subjected to mechanical friction by a refiner, beater, etc.) has a freeness in the range of 650 to 750 ml CSF. is there. In the present invention, the mixing ratio of the regenerated cellulose fiber and the wood pulp is in the range of 15 to 55% by weight of the regenerated cellulose fiber and 85 to 45% by weight of the wood pulp.

When the content of the regenerated cellulose fiber is less than 15% by weight, the product cost becomes low, but even if the fiber is entangled by a high-pressure water jet treatment, the nonwoven fabric has a sufficient wet strength and excellent water dissolvability. Can not be obtained. Conversely, if the content of the regenerated cellulose fiber exceeds 55% by weight, the wood pulp is beaten to make it easy to develop the bond strength, and if high energy is not given during high-pressure water jet flow treatment, sufficient fiber No confounding. In addition, the cost of regenerated cellulose fibers, which are more expensive than wood pulp, is higher, which increases the product cost of the nonwoven.

JIS P 8124 for wet papermaking web
The basis weight measured by the method according to the above is in the range of 30 to 80 g / m ² . When the basis weight is less than 30 g / m ² , the strength tends to be insufficient when the obtained water-disintegratable nonwoven fabric is used for applications such as a wiper, and is broken during use and cannot be used. Conversely, if the basis weight exceeds 80 g / m ² , the rigidity of the sheet increases, making it difficult to use, and the water-disintegratable nonwoven fabric tends to have poor water-disintegration properties when poured into a water stream.

In the present invention, a mixture of regenerated cellulose fiber and wood pulp is used as a raw material and wet-paper-formed using a known paper machine such as a round paper machine, a short net paper machine, an inclined wire paper machine, a fourdrinier paper machine, or the like. After forming the web, a high-pressure water jet stream is jetted from the surface of the web in order to perform the treatment by the hydroentanglement method.

The most important point in the present invention lies in the method of high-pressure water jet treatment. In general, high pressure water jet treatment is performed by placing a web on a porous support such as a wire mesh and, from the top of the web, a pore size of 0.08 to 0.3.
Water pressure 15 ~ through a nozzle with a large number of 0mm pores arranged
In this method, high-pressure water is jetted at a water pressure of 150 kg / cm ² to entangle the fibers constituting the web. The energy imparted to the web by high pressure water jet treatment is
It is represented by the addition specific energy calculated by the equation (1),
The higher the added specific energy, the easier it is to obtain entanglement of the fibers and a high strength sheet is obtained, but the water disintegration becomes poor. Conversely, when the addition specific energy is reduced, a sheet excellent in water disintegration can be obtained, but the strength is inferior. A characteristic point of the present invention is that a high-pressure water jet treatment is performed at a relatively high additional specific energy, and a quasi-water dissolvable region having a high strength is applied, and a high-pressure water jet is treated at a relatively low additional specific energy. It is to distribute the easily water-disintegrable region having excellent water-disintegrability over the entire nonwoven fabric.

E = (A × (2 / ρ) ^1/2 × (g × P) ^3/2 ) / (M × 60 × S) (1) where E: additional specific energy (kWh / kg) A: Sum of nozzle hole areas (m ² ) ρ: Water density (kg / cm ³ ), g: Gravitational acceleration (m / s ² ), P: Water pressure at nozzle part (Pa), S: Web Passing speed (m / min), M: web mass (g / m ² ).

The following method can be used as the first method for forming the semi-water-disintegrable region and the easily water-disintegrable region by partially controlling the additional specific energy applied to the nonwoven fabric. For example, in high-pressure water jet flow treatment, the area of one web is 0.2 cm
A high-pressure water jet flow shielding plate having a large number of openings of ^{2 to 2} cm ² is installed, and the high-pressure water jet flow shielding plate is moved with the web and the porous support, from the upper surface of the high-pressure water jet flow shielding plate. A method of performing high-pressure water jet flow treatment on a web can be used. The high-pressure water jet flow shielding plate may be a metal plate made of stainless steel, copper, or the like, a plastic sheet made of polyethylene, polyester, nylon, or the like, having an opening of 0.2 cm ^{2 to 2} cm ² , or an eye. Opening 100 μm to 800 μm
Made of metal such as stainless steel or bronze,
For example, a metal wire mesh made of polyester or nylon and having an opening of 0.2 cm ^{2 to 2} cm ^{2 in} an area per piece can be used. Here, the opening of the high-pressure water jet flow shielding plate has an area of 0.2 cm ^{2 to 2} cm ² per piece.
The other portion is called a non-opening portion. The shape of the opening provided in the high-pressure water jet flow shielding plate may be any shape such as a circle, an ellipse, a square, and a rhombus, and a plurality of these shapes may be provided in combination.

The webs located at the openings of these high-pressure water jet flow shields have a high strength by being treated at a relatively high additional specific energy by the high-pressure water jet flow from the high-pressure water jet flow device. Form a quasi-water disintegrable region. In addition, the web located at the non-opening of the high-pressure water jet flow shielding plate is blocked by the high-pressure water jet flow from the high-pressure water jet flow treatment device, and is treated with a relatively weak additional specific energy, so that fiber entanglement is reduced. Form easily water-disintegrable regions with excellent water-disintegration properties.

Among these high-pressure water jet flow shielding plates, the WJ treatment which is excellent in drainage of the high-pressure water jet flow injected toward the non-opening portion of the high-pressure water jet flow shielding plate, and is relatively weak even in the non-opening portion. Since it is easy to make the strength of the water-disintegratable nonwoven fabric obtained by imparting an excellent strength, a metal wire mesh such as stainless steel or bronze, polyester,
It is desirable to use a metal net made of nylon or the like provided with an opening having an area of 0.2 cm ^{2 to 2} cm ² as a WJ shielding plate. The mesh of the wire mesh to be used can be arbitrarily selected, but a wire mesh of about 800 μm or less can be used. If the mesh size of the wire mesh exceeds 800 μm, the ratio of the high-pressure water jet flow passing through the wire mesh and applied to the web becomes too high. The fiber entanglement of the easily water-disintegrable region formed in the non-woven fabric tends to be too high, and the water-disintegrability of the resulting water-disintegratable nonwoven fabric tends to be poor. Wire mesh opening is 800
If it is not more than μm, it can be suitably used, but generally, as the mesh size of the wire mesh becomes narrower, the diameter of the filament constituting the wire mesh becomes thinner, and the drainage and durability tend to be inferior. For this reason, the lower limit of the mesh size of a practically usable wire mesh is about 100 μm.

If the area of each opening is less than 0.2 cm ² , the area subjected to high-pressure water jet treatment through the opening becomes too small, and sufficient fiber entanglement is imparted to the web located at the opening. Therefore, it is difficult to form a quasi-water-disintegrable region. Also, when a quasi-water disintegrable region was formed,
The strength of the nonwoven fabric itself tends to be insufficient, and the strength of the whole water-disintegratable nonwoven fabric is also low. Conversely, if the area of each opening exceeds 2 cm ² , the area per unit of the quasi-water-disintegrable region formed by the high-pressure water jet flow treatment becomes too large, and the water-disintegrability of the obtained water-disintegratable nonwoven fabric is reduced. Inferior results. The number of openings provided in the high-pressure water jet flow shielding plate can be arbitrarily selected so that the opening ratio is in the range of 30% to 80%.

If the opening ratio is less than 30%, the proportion of the quasi-water-disintegrable region formed by the high-pressure water jet flow treatment in the entire nonwoven fabric becomes too low, and a water-disintegratable nonwoven fabric having sufficient strength cannot be obtained. Conversely, if the opening ratio exceeds 80%, the proportion of the easily water-disintegrable region formed by shielding a part or all of the high-pressure water jet stream in the entire nonwoven fabric becomes too low, and the water disintegration of the obtained water-disintegratable nonwoven fabric It becomes inferior in nature. Also, since the size of the non-opening portion between the openings of the high-pressure water jet flow shielding plate is too small, the quasi-water dissolving region formed at the position corresponding to the opening is adjacent to the quasi-water dissolving region. It is difficult to separate from the area,
The size of each quasi-water-disintegrable region obtained is likely to be too large. If the size per quasi-water-disintegrable region is too large, it will be difficult to obtain sufficient water-disintegrability.

The additional specific energy applied to the web located at the opening of the high pressure water jet flow shielding plate to form a quasi-water disintegrable region by high pressure water jet flow treatment is 0.1 k.
Wh / kg or more. 0.1kW additional energy
If it is less than h / kg, the strength of the quasi-water-disintegrable region formed by the high-pressure water jet flow treatment cannot be sufficiently obtained, and the strength of the whole water-disintegratable nonwoven fabric is undesirably low. When the high pressure water jet flow treatment is performed from above the high pressure water jet flow shield plate, the added specific energy of the high pressure water jet flow shield plate with respect to the web located at the non-opening portion varies depending on the type of the high pressure water jet flow shield plate. That is, when the high-pressure water jet flow shielding plate is a metal plate, a sheet, or the like, the high-pressure water jet flow does not act on the web through the non-opening portion of the high-pressure water jet flow shielding plate, so that no additional specific energy is applied.

If the high pressure water jet flow shield is a wire mesh, the high pressure water jet acts on the web through the openings of the wire mesh. The degree of the additional specific energy at that time is
Depends on the degree of mesh opening. The higher the strength of the quasi-water-disintegrable region is, the more preferable. However, there is an upper limit to the strength obtained by increasing the additional specific energy. Also, as the added specific energy is increased, the amount of wood pulp and regenerated cellulose fibers that flow away from the web together with the high-pressure water jet tends to increase.

Therefore, the practical upper limit of the additional specific energy is 0.4 kWh / kg. If the additional specific energy is in the range of 0.1 kWh / kg to 0.4 kWh / kg, even if a metal plate or a plastic sheet is used as the high-pressure water jet flow shielding plate according to the present invention, the aperture is 100%.
Even when a wire mesh of μm to 800 μm is used, the easily water-disintegrable region formed in the portion located at the non-opening portion of the high-pressure water jet flow shielding plate disintegrates in a fibrous form in 30 to 150 seconds when disintegrated, In addition, the quasi-water dissolvable region formed in the portion located at the opening of the high-pressure water jet flow shielding plate also has a sufficient strength.

The high-pressure water jet flow treatment on the web may be performed only from above the high-pressure water jet flow shielding plate, or before or after applying the high-pressure water jet flow treatment from above the high-pressure water jet flow shielding plate. 0.03kWh / kg-0.07k
A high pressure water jet treatment is applied to the entire web with a weak additional specific energy in the range of Wh / kg, and a part of or a part of the high pressure water jet flow is blocked by the high pressure water jet flow shielding plate to form an easily water-dissolvable region. Strength can also be improved.

The method of subjecting the entire web to high-pressure water jet treatment with a low additional specific energy before or after applying high-pressure water jet treatment from above the high-pressure water jet flow shielding plate is described in the present invention. It can be used as a means to moderately improve fiber entanglement and increase the strength of the whole water-disintegratable nonwoven fabric, especially metal plates such as stainless steel and copper as high-pressure water jet flow shielding plates, polyethylene, polyester, nylon, etc. Using a plastic sheet with an opening of 0.2 cm ^{2 to 2} cm ^2, and applying a high-pressure water jet flow treatment from above the high-pressure water jet flow shielding plate to the area where an easily water-dissolvable area is formed This is a method that can be effectively used when no high-pressure water jet flow is applied. If the additional specific energy applied to the web at this time exceeds 0.07 kWh / kg, the fiber entanglement in the easily water-disintegrable region becomes too high, resulting in poor water-disintegrability of the resulting water-disintegratable nonwoven fabric. Conversely, the additional specific energy is 0.03
If it is less than kWh / kg, the effect of the high-pressure water jet treatment is hardly obtained and is not practical.

When a high pressure water jet flow treatment is applied to the entire web with a low additional specific energy before or after the high pressure water jet flow treatment is applied from above the high pressure water jet flow shielding plate, the additional water applied to the quasi-water dissolvable region The specific energy can be represented by the sum of the additional specific energy given by the high-pressure water jet flow from above the shielding plate and the additional specific energy given to the entire nonwoven fabric.

The second method of forming the semi-water-disintegrable region and the easily water-disintegrable region by partially controlling the additional specific energy applied to the nonwoven fabric is, for example, a simple and general method described below. In a method in which high-pressure water jet flow treatment equipment can be diverted almost as it is, it can be formed so that a quasi-water-disintegrable region and an easily water-disintegrable region are present at regular intervals in the width direction of the nonwoven fabric and alternately. The nozzles in the high-pressure water jet flow generator usually have a hole diameter of 0.08 to 0.30 m at regular intervals.
m pores are arranged. When a high-pressure water jet treatment is performed using such a nozzle, a nonwoven fabric treated with uniform energy over one surface can be obtained. In addition, the pore size is 0.
When a high-pressure water jet flow treatment is performed using a nozzle in which apertures having pores of 08 to 0.30 mm open at regular intervals and non-openings having no holes are alternately arranged, the non-openings are obtained. Does not generate a high-pressure water jet flow, so that a region subjected to the high-pressure water jet flow treatment and a region not subjected to the high-pressure water jet flow treatment alternately exist in the web width direction on the web subjected to the high-pressure water jet flow treatment.

A nozzle in which such openings and non-openings are alternately arranged is referred to as a partially open nozzle, and a normal nozzle having no non-opening is referred to as a fully open nozzle. The opening of the partially apertured nozzle is called an open area, and the non-opening is called a non-opened area. The high-pressure water jet flow generator part equipped with the partial aperture type nozzle and the high pressure water jet flow generator part equipped with a full aperture type nozzle with pores arranged at regular intervals are continuously processed on the same line. When the web is treated with a high-pressure water jet, the portion receiving the high-pressure water jet at the opening of the partially-perforated nozzle part also receives the high-pressure water jet of the fully-perforated nozzle part. The added specific energy received is large, and the fibers are strongly entangled. In the non-opening part of the partially apertured nozzle part,
Since no high-pressure water jet flow is received and only the high-pressure water jet flow of the fully-opened nozzle part is received, the added specific energy received by the web is small and the fibers are slightly entangled.

As described above, in a simple method of replacing a part of the high-pressure water jet stream treatment equipment with the partially open type nozzle, the part treated so that the added specific energy given to the web by the high-pressure water jet stream is different. Are obtained in a strip shape and are alternately arranged. The high-pressure water jet flow generator part provided with the partial aperture type nozzle may be located before or after the high pressure water jet flow generator part provided with the full aperture type nozzle, Further, they may be on the same porous support or on different porous supports. The high-pressure water jet flow generator provided with the partial aperture type nozzle and the high pressure water jet flow generator provided with the full aperture type nozzle may be arranged in a single row or in a plurality of rows. In the case of a plurality of rows, there is a tendency that the processing speed is faster and more efficient, and that a sheet having a good formation is obtained.

However, when using a plurality of rows of high pressure water jet flow generators provided with the partially apertured nozzles, the apertures and non-openings of each nozzle do not shift in the flow of the line. It is necessary to adjust as follows. If the opening and the non-opening part are shifted on the line, the width of the part where the high-pressure water jet flow treatment obtained at the non-opening part is not performed becomes narrower. This is not preferable because there are no unprocessed parts. The high-pressure water jet flow treatment by the high-pressure water jet flow generator equipped with the partially open nozzle and the high-pressure water jet flow treatment by the high-pressure water jet flow generator equipped with the full-open nozzle are continuously performed on the same line. Processing may be performed, or processing may be performed offline.

In the above-described method, two or more high-pressure water jet flow generators are required. However, even in one row, nozzles having nozzle holes having different diameters are alternately arranged and areas having different hole intervals are alternately arranged. The same effect can be obtained by using the arranged nozzles.

The partially open type nozzle used in the present invention comprises:
Open areas where pores having a hole diameter of 0.08 to 0.30 mm are formed at regular intervals and non-open areas where no holes are present are alternately arranged. The width of one non-opening area of the partially open nozzle, that is, the width of the easily water-dissolvable area is preferably 3 mm to 15 mm. If it is less than 3 mm, the effect of the water-disintegrable region does not appear, which is not preferable. The upper limit of the width of one non-open area is
The fiber length of the regenerated cellulose fiber used for the nonwoven fabric is preferably about the same. There is naturally a limit to the fiber length at which good formation can be obtained with a wet paper machine, and is about 15 mm. That is, the upper limit of the width of one non-opening region in the present invention is 15 mm.

It is not preferable that the width of the non-porous portion greatly exceeds 15 mm, that is, the fiber length of the regenerated cellulose, because the strength in the width direction of the nonwoven fabric becomes too weak. The width of one opening area of the partial opening type nozzle, that is, the width of the semi-water dissolvable area is preferably 3 to 20 mm. If the width of the region for increasing the strength in the sheet flow direction is less than 3 mm, the sheet strength is not improved, which is not preferable. On the other hand, if it exceeds 20 mm, the strength is high, but after being hydrolyzed in a belt shape, it is not preferable because it is harder to hydrolyze. If the width of the quasi-water disintegrating region is 20 mm or less, after hydrolyzing in a belt shape, the water can be more finely hydrolyzed due to the water flow, the rubbing between the belt-shaped sheets, and the like.

The non-woven fabric of the present invention is a water-disintegratable non-woven fabric in which a readily water-disintegratable region that easily disintegrates into fibrous shapes and a quasi-water-disintegrable region that is difficult to disintegrate in fibrous shapes are alternately distributed over the entire non-woven fabric. By providing portions having different added specific energies during high-pressure water jet flow treatment, easily water-disintegrable regions and quasi-water-disintegrable regions can be distributed on the nonwoven fabric. That is, the portion subjected to the high-pressure water jet flow treatment at a low additional specific energy is an easily water-disintegrable region in which fiber entanglement is weak and excellent in water dissolvability, and the portion subjected to the high pressure water jet flow treatment at a high additional specific energy is a water-disintegrable region. Although it is inferior, since fiber entanglement is strong, it is a quasi-water-disintegrable region having strength. A region excellent in water disintegration and a region having strength are individually distributed over the entire nonwoven fabric, and each property separately contributes to the physical properties of the nonwoven fabric, so that a strong nonwoven fabric excellent in water disintegration can be obtained.

The easily water-dissolvable region treated with a low additional specific energy is a region treated in the non-opening portion of the high-pressure water jet flow generator part provided with the above-described partially opened nozzle. The additional specific energy of the easily water-dissolvable region is the sum of the specific energy of the high-pressure water jet flow processed by the high-pressure water jet flow generator part provided with the fully open nozzle. The quasi-water dissolvable region treated with a high additional specific energy is a region treated at the nozzle opening portion of the high-pressure water jet stream generator part provided with the above-described partial opening nozzle. The additional specific energy in the quasi-water disintegration region is the sum of the specific energy of the high-pressure water jet flow processed by the high-pressure water jet flow generator part equipped with a partially apertured nozzle and the high-pressure water jet flow generator part equipped with a fully apertured nozzle. It is.
The additional specific energy of the easily water-dissolvable region is 0.03 to 0.1.
1 kWh / kg is desirable.

The additional specific energy is 0.03 kWh / kg
If it is less than 30, the lateral strength of the nonwoven fabric is weak, and it is not preferable because the strength during use cannot be endured. On the other hand, when the added specific energy exceeds 0.11 kWh / kg, the water disintegration is remarkably reduced, which is not preferable. The additional specific energy of the quasi-water disintegration region is desirably 0.12 to 0.30 kWh / kg. If the additional specific energy is less than 0.12 kWh / kg, it is not preferable because excellent longitudinal strength cannot be obtained. Further, even if the treatment is performed with the added specific energy exceeding 0.30 kWh / kg, the strength hardly improves, and the feeling of the sheet is remarkably reduced, which is not preferable.

The high-pressure water jet treatment may be performed online in the state of a wet web after forming a web by wet papermaking, or once the wet-formed web is dried, and then subjected to online or offline high-pressure water jet treatment. Processing may be performed. When the water-disintegratable nonwoven fabric thus obtained is disintegrated in water, it is relatively difficult to disintegrate into a fibrous state as compared with the easily disintegratable region and the easily disintegratable region that disintegrates in a fibrous form in 30 to 150 seconds. A quasi-water disintegrable region is formed.

The readily water-disintegrable region in the present invention refers to a region which is easily disintegrated into a fibrous form by a water flow, and the quasi-water-disintegrable region is a relatively fibrous disintegrated region compared to the easily disintegratable region. It is an area that is difficult to do. When a water-disintegratable nonwoven fabric in which a water-disintegrable region and a quasi-water-disintegrable region are distributed over the entire nonwoven fabric is introduced into a water stream, the disintegration is performed as follows. That is, first, the water-disintegrable region of the water-disintegratable nonwoven fabric disintegrates in a fibrous form, and is divided into many small pieces. The size of this small piece does not change for a while even after disintegration by water flow.
In the water-disintegratable nonwoven fabric, the area formed by the small pieces is called the quasi-water-disintegrable area, and the area formed by the fibers completely disintegrated at this point and dispersed in water is defined as the easily water-disintegrable area. I do. Since the quasi-water-disintegrable region is relatively difficult to disintegrate in a fibrous form as compared with the easily water-disintegrable region, the shape hardly changes for a while even during disintegration by the water flow.

Thereafter, as the disintegration is further promoted by the water flow, the quasi-water disintegrating region divided into small pieces also gradually loosens the constituent fibers or separates into some smaller pieces. In the present invention, the semi-water-disintegrable region and the easily water-disintegrable region were determined as follows. That is, a water-disintegratable nonwoven fabric cut into a size of 5 cm × 5 cm (25 cm ² ) is put into 100 ml of pure water and shaken at a shaking speed of 300 cycles / minute. During the shaking, the disintegration of the sample is visually observed every 15 seconds. The sample piece is divided into a number of small pieces with shaking. Shaking is stopped when the shape of the small piece hardly changes even after repeated shaking for 30 seconds.

At this time, the portion remaining as small pieces is quasi-water disintegrable.
This is an area, which is disintegrated in fiber form and dispersed in water
The part is a water-disintegrable area. Water-disintegrable area separates into fibrous form
The time to solve is long enough that the shape of the small piece does not change
It represents the time when it became the first time. In addition, one of
The area per piece is calculated from the average of the area per piece.
Calculated, the percentage of the easily water-disintegrable area in the total nonwoven fabric is
Area of test piece (25cm ^Two) And the total area of the quasi-water dissolvable region
(Area per quasi-water disintegrable region x quasi-%
Number of water-disintegrable regions). Easy-to-dissolve area is fibrous
The faster the disintegration speed of the non-woven fabric is
The water disintegration of the body is also excellent, but immediately after being put in water
Is not suitable for practical use if it disintegrates into a fibrous form
Therefore, the lower limit is about 30 seconds.

In the present invention, the proportion of the water-disintegrable region in the whole nonwoven fabric is 15 to 70%. If the proportion of the water-disintegrable region is less than 15%, the ratio of the water-disintegrable region to the whole nonwoven fabric is too low, and the water-disintegratable nonwoven fabric tends to have poor water-dissolvability. Conversely, when the proportion of the easily water-disintegrable region exceeds 70%, the ratio of the semi-water-disintegrable region formed adjacent to the easily water-disintegrable region becomes too low, and the strength of the water-disintegratable nonwoven fabric becomes poor. The area per quasi-water disintegrable region is 0.2 cm ^{2 to 2} cm ² . If the area per one piece is less than 0.2 cm ² , the strength of the semi-water-disintegrable region itself becomes insufficient, and the strength of the whole water-disintegrable nonwoven fabric also becomes low. Conversely, if the area per piece exceeds 2 cm ² , the water-disintegratable nonwoven fabric will have poor water-disintegration results.

The water-disintegrability of the thus obtained water-disintegrable nonwoven fabric must be 300 seconds or less. The water disintegration in the present invention is 5 cm × 5 cm (25 cm).
100 ml of the water-disintegratable nonwoven fabric cut to the size of cm ² )
Of pure water and shaken at a shaking speed of 300 cycles / minute to disintegrate the water-disintegratable nonwoven fabric in water and define the time required for disintegration until the maximum piece size becomes 1 cm ² .
The water disintegration was evaluated by stopping the shaking once every 30 seconds, observing the disintegration state of the water disintegratable nonwoven fabric, and evaluating the average value of n = 5.

If the water disintegration is longer than 300 seconds, the nonwoven fabric becomes difficult to disintegrate or collapse in running water, and it is unsuitable because it causes pipes to be clogged when flushed into a flush toilet.
The shorter the water disintegration in time, the better.
However, there is naturally a limit to the value of water dissolvability achieved while maintaining the wet strength of the nonwoven fabric in a desired range,
In the method of the present invention, 30 seconds is the lower limit.

The required wet strength of the water-disintegratable nonwoven fabric varies depending on the application, but wet products such as wet tissues, baby wipes, and wipers for cleaning which are one of the main applications of the water-disintegratable nonwoven fabric according to the present invention. When used as, the wet tensile strength measured in accordance with JIS P 8135 is preferably 200 gf / 25 mm or more in wet tensile strength in the longitudinal direction and 50 gf / 25 mm or more in wet tensile strength in the transverse direction. Is more preferably 200 gf / 25 mm or more.

Geometric mean of wet tensile strength = √ (XY) (2) where X: wet tensile strength in the longitudinal direction of the water-disintegratable nonwoven fabric (g)
f: 25 mm) Y: Wet tensile strength in the transverse direction of the water-disintegratable nonwoven fabric (gf / 25)
mm).

When used as a wet product, it is easy to process into a wet product (suitability for processing: difficult to cause trouble due to paper breakage, etc.), difficult to break when taken out of the container after processing (suitability for removal), When used, it is required to be difficult to break (suitability for use). Processing suitability and take-out suitability are as follows.
If it is 5 mm or more, it can be used. The suitability for use is 50 gf / 25 m in the vertical and horizontal directions of the water-disintegratable nonwoven fabric.
There is almost no problem if the wet strength is not less than m. Further, if the value of the geometric mean value of the wet tensile strength is 200 g / 25 mm or more, it can be used without any practical problem even in an application for wiping with a very strong force such as some cleaning wipers, and it is more preferable.

The upper limit of the wet strength varies depending on the distribution state of the easily water-disintegrable region and the semi-water-disintegrable region in the water-disintegratable nonwoven fabric. The distribution state where the highest wet tensile strength is obtained is
As set forth in claims 3 and 4,
This is the case where the easily water-disintegrable region and the quasi-water-disintegrable region are alternately distributed in a strip shape over the entire water-disintegratable nonwoven fabric.
It is.

In order to use the water-disintegratable nonwoven fabric according to the present invention as a wet product such as a wet tissue, a wiping wipe, a wiper, etc., water, a humectant such as propylene glycol, an alcohol or parabenzoic acid ester may be used, if desired. Such antibacterial agents, fungicides, fragrances, and various agents having a specific medicinal effect can be used alone or in combination for impregnation.

When the water-disintegratable nonwoven fabric of the present invention is used as a surface material of a sanitary material, it can be used as it is, but if necessary, the nonwoven fabric may be subjected to a treatment for increasing the hydrophilicity and water repellency. . As described above, the present invention can reduce the amount of regenerated cellulose fibers to reduce the product cost, provide a well-balanced wet strength and water-disintegrability to produce a water-disintegratable nonwoven, and the obtained nonwoven is In a dry state and a wet state, the fibers retain strength enough to withstand operations such as cleaning, and in a large amount of water flow, the fibers constituting the nonwoven fabric disintegrate or disintegrate very easily in the water flow. It can be suitably used as a wet product such as a cloth, a cleaning wiper or the like, or a top sheet of a disposable diaper or a sanitary napkin.

[0063]

The present invention will be described in more detail with reference to the following examples, which, of course, are not intended to limit the scope of the present invention. In Examples and Comparative Examples, “%” means “% by weight” unless otherwise specified.

1. The area per one quasi-water disintegratable region (cm ² ) A water disintegratable nonwoven fabric cut into a size of 5 cm × 5 cm (25 cm ² ) is put into 100 ml of pure water and shaken at a speed of 3.
Shake at 00 cycles / minute. During the shaking, the disintegration of the sample is visually observed every 15 seconds. The sample piece is divided into a number of small pieces with shaking. Shaking is stopped when the shape of the small piece hardly changes even after repeated shaking for 30 seconds. After shaking, the area of any five small pieces among the small pieces remaining without being disintegrated into a fibrous shape was measured. The test was performed with n = 3, and indicated by an average value of 15 points in total. When the number of small pieces divided by shaking one test piece was less than 5, the area was measured for all of them and the average value was obtained.

2. Ratio of easily water-disintegrable region to total nonwoven fabric (%) First, “1. Area per single semi-water-disintegrable region (c)
m ² ) ”, the number of small pieces remaining when one test piece was disaggregated was measured, and the number N of small pieces per one test piece was determined.
This is multiplied by Junmizu disintegratable area per area of (cm ^2), obtaining the sum of the areas of semi-disintegrable area (cm ^2). 1
One is the area of the test piece is 25 cm ^2, the percentage of it remained semi water-disintegrable region other than the portion as small pieces which is easily water-disintegrable region, the easily water-disintegrable region to the area (25 cm ²⁾ of the specimen test piece (%) Was determined.

3. Water dissolvability (sec) First, a test piece of non-woven fabric having a size of 5 cm x 5 cm (25 cm ² ) is prepared, then 100 ml of pure water is put into a 150 ml Erlenmeyer flask, and the test piece is put into the flask. Shake at a shaking speed of 300 cycles / minute,
Shaking was stopped every 30 seconds, and the state of disaggregation of the water-disintegratable nonwoven fabric was observed, and then the shaking was repeated. The time required for defibration until the size of the largest piece of the nonwoven fabric became 1 cm ² by shaking was measured to obtain a water-disintegrable value (second), and expressed as an average value of n = 5. Water disintegration was determined to be excellent if it was 300 seconds or less.

4. Wet tensile strength and geometric average of wet tensile strength (gf / 25 mm) First, the wet tensile strength was cut in the longitudinal and transverse directions of the test piece to form a 25 mm wide strip.
It was measured and determined according to ISP 8135. Geometric average of wet tensile strength (gf / 25 mm) From each value of the measured wet tensile strength in the longitudinal direction and the lateral direction, the geometric average was calculated by the formula (3). Geometric average of wet wet tensile strength = √ (XY) (3) where X: wet tensile strength of the water-disintegratable nonwoven fabric in the longitudinal direction (g
f: 25 mm) Y: Wet tensile strength in the transverse direction of the water-disintegratable nonwoven fabric (gf / 25)
mm).

5. Texture (point) The texture was determined by a tactile test by 20 monitors.
In the test method, the water-disintegratable nonwoven fabric was grasped by hand and expressed as a total score (100 points) based on the following evaluation criteria. If the total score is 75 points or more, it is determined that the texture is good. 5 points: Very excellent touch feeling. 4 points: Excellent touch feeling. 3 points: The feel is normal. 2 points: The touch feeling is slightly inferior. 1 point: Inferior feel. 0: Very poor feel

Example 1 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio of diameter to fiber length L / D of 594.
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was set on the non-woven fabric. Using a high-pressure water jet flow treatment device in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 50 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.29 kWh / kg. The high-pressure water jet flow shielding plate is a stainless steel 100-mesh wire mesh (aperture 140 μm) in which circular openings (area = 1.1 cm ² ) having a diameter of 12 mm are provided in a staggered arrangement at 20 mm intervals (opening ratio: 56.5%). The obtained water-disintegratable nonwoven fabric was tested according to the test method described above, and the quality was evaluated. Table 1 shows the results.

Example 2 Fineness: 3.0 denier, fiber length: 5 mm, L / D: 30
50% rayon fiber and softwood bleached kraft pulp in Canadian standard freeness 600ml using laboratory beater
Using a mixture of 50% of pulp beaten to CSF as a raw material, a web was formed on an inclined wire paper machine and then dried to obtain a nonwoven fabric consisting of rayon and pulp having a basis weight of 65 g / m ² .

This non-woven fabric is placed on a transfer supporting net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate is further placed on the non-woven fabric, and then transferred at a speed of 30 m / min. While using a high-pressure water jet flow treatment device in which nozzle holes having a hole diameter of 0.15 mm are arranged at 1.0 mm intervals, a high-pressure water jet flow is jetted from above the nonwoven fabric at a water pressure of 90 kg / cm ² , and then dried, A water-disintegratable nonwoven fabric was obtained. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.17 kWh / kg. The high-pressure water jet flow shielding plate is a stainless steel 100 mesh wire mesh (aperture = 140 μm) with circular openings (area = 1.1 cm ² ) having a diameter of 12 mm provided in a staggered manner at 24 mm intervals (opening ratio). = 39.3%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 3 The fineness was 1.5 denier, the fiber length was 7 mm, and the L / D was 59.
No. 4 rayon fiber 20% and unbeaten softwood bleached kraft pulp (Canada standard freeness: 690 ml CSF) 80%
Was used as a raw material to form a web in an inclined wire type paper machine and then dried to obtain a nonwoven fabric consisting of rayon and pulp having a basis weight of 40 g / m ² .

This sheet is placed on a transfer support net formed of a 80-mesh wire net, and a high-pressure water jet flow shielding plate is further placed on the nonwoven fabric. And a nozzle hole having a hole diameter of 0.15 mm.
Using a high-pressure water jet flow treatment device arranged at 0 mm intervals, a high-pressure water jet flow was injected at a water pressure of 55 kg / cm ² , and then dried to obtain a water-disintegratable nonwoven fabric. The added specific energy given to the nonwoven fabric through the opening of the high-pressure water jet flow shielding plate by this high-pressure water jet flow treatment was 0.21.
kWh / kg. The high-pressure water jet flow shielding plate is made of polyester and has a mesh of 25 mesh (aperture = 500).
μ) has a 15 mm diameter circular opening (area = 1.8 c).
m ² ) were used in a staggered arrangement at 24 mm intervals (opening ratio = 61.3%). The obtained water-disintegratable nonwoven fabric is
The quality was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 4 Fineness: 1.5 denier, fiber length: 10 mm, L / D: 8
49 rayon fiber 20% and unbeaten softwood bleached kraft pulp (Canada standard freeness: 690 ml CSF) 80
% Of the mixture as a raw material, a web was formed on an inclined wire paper machine, and then dried to obtain a nonwoven fabric made of rayon and pulp having a basis weight of 40 g / m ² .

This sheet is placed on a transfer support net formed of a 80-mesh wire net, and a high-pressure water jet flow shielding plate is further placed on the nonwoven fabric. And a nozzle hole having a hole diameter of 0.15 mm.
Using a high-pressure water jet flow treatment device arranged at 0 mm intervals, a high-pressure water jet flow was jetted at a water pressure of 80 kg / cm ² , and then dried to obtain a water-disintegratable nonwoven fabric. The added specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment is 0.36.
kWh / kg. The high-pressure water jet flow shielding plate is made of polyester and has a mesh of 25 mesh (aperture = 500).
μ) has a circular opening with a diameter of 12 mm (area = 1.1 c)
m ² ) were provided in a staggered arrangement at 24 mm intervals (opening ratio = 39.3%). The obtained water-disintegratable nonwoven fabric is
The quality was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 5 The fineness was 1.5 denier, the fiber length was 5 mm, and the L / D was 42.
Using a mixture of 30% rayon fiber of No. 4 and unbeaten softwood bleached kraft pulp (Canada standard freeness: 650 ml CSF) as a raw material, a web is formed on an inclined wire-type paper machine, and the web is pressed by a press roll. Linear pressure 3kg
After dehydration with a press pressure of / cm to obtain a web having a moisture content of 68%, the web was subjected to high-pressure water jet flow treatment with a high-pressure water jet flow treatment device installed immediately after the press roll, and then the web was subjected to high-pressure water jet flow treatment. A high pressure water jet flow shielding plate is placed,
The web was again subjected to high-pressure water jet treatment by a high-pressure water treatment device installed at a later stage, and then dried and dried to a weight of 50 g.
/ M ² of water-disintegrable non-woven fabric consisting of rayon and pulp.

Each support of the high-pressure water jet flow treatment device is formed of an 80 mesh wire mesh, and the web is
In the first high-pressure water jet flow treatment device while transferring at a speed of 20 m / min, 25 kg / cm ² was applied using a high-pressure water jet flow treatment device in which nozzle holes having a hole diameter of 0.15 mm were arranged at 1.0 mm intervals. A high pressure water jet was injected at the water pressure. The additional specific energy imparted to the nonwoven fabric by this high-pressure water jet treatment was 0.05 kWh / kg. In the second high-pressure water jet flow treatment device,
Using a high-pressure water jet flow treatment device in which nozzle holes having a hole diameter of 0.15 mm are arranged at 1.0 mm intervals, 50 kg / cm
^At a water pressure of ² , a high pressure water jet was injected. The added specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment is 0.1%.
It was 4 kWh / kg. By the two high-pressure water jet flow treatments, the sum of the additional specific energy applied to the nonwoven fabric positioned at the opening of the high-pressure water jet flow shielding plate is 0.1%.
It was 19 kWh / kg. The high-pressure water jet flow shielding plate is made of stainless steel and has a mesh of 50 mesh (aperture 250
μm), a circular opening with a diameter of 6 mm (area = 0.3 cm)
² ) provided in a staggered arrangement at 12 mm intervals (opening ratio:
39.3%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 6 The fineness was 1.5 denier, the fiber length was 7 mm, and the L / D was 59.
Using a mixture of 30% rayon fiber of No. 4 and unbeaten softwood bleached kraft pulp (Canada standard freeness: 690 ml CSF) as a raw material, a web is formed on an inclined wire paper machine, and the web is pressed by a press roll. Linear pressure 3kg
After dehydrating with a press pressure of / cm to obtain a web with a moisture content of 66%, the web was subjected to high-pressure water jet flow treatment with a high-pressure water jet flow treatment device installed immediately after the press roll, and then was applied to the upper surface of the nonwoven fabric. A high pressure water jet flow shielding plate is placed,
The web was again subjected to high-pressure water jet treatment by a high-pressure water treatment device installed at a later stage, and then dried and dried to a weight of 50 g.
/ M ² of water-disintegrable non-woven fabric consisting of rayon and pulp.

Each support of the high-pressure water jet flow treatment device is formed of an 80 mesh wire mesh, and the web is
In the first high-pressure water jet flow treatment device while transferring at a speed of 20 m / min, 25 kg / cm ² was applied using a high-pressure water jet flow treatment device in which nozzle holes having a hole diameter of 0.15 mm were arranged at 1.0 mm intervals. A high pressure water jet was injected at the water pressure. The additional specific energy imparted to the nonwoven fabric by this high-pressure water jet treatment was 0.05 kWh / kg. In the second high-pressure water jet flow treatment device,
Using a high-pressure water jet flow treatment device having two rows of high-pressure water jet flow treatment devices in which nozzle holes having a hole diameter of 0.15 mm are arranged at 1.0 mm intervals in the flow direction, 50 kg / cm
^At a water pressure of ² , a high pressure water jet was injected. The added specific energy given to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment is 0.2%.
It was 9 kWh / kg. By the two high-pressure water jet flow treatments, the sum of the additional specific energy applied to the nonwoven fabric positioned at the opening of the high-pressure water jet flow shielding plate is 0.1%.
It was 34 kWh / kg. The high-pressure water jet flow shield plate is a stainless steel plate having a thickness of 0.1 mm in which circular openings (area = 1.1 cm ² ) having a diameter of 12 mm are provided in a staggered arrangement at 20 mm intervals (opening ratio: 56.5%). )It was used. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 7 In the same manner as in Example 1, a web was formed by wet papermaking on an inclined wire type paper machine, followed by drying and drying, and a basis weight of 50 g / m2.
^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was set on the non-woven fabric. Using a high-pressure water jet flow treatment device in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 50 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.29 kWh / kg. The high-pressure water jet flow shield plate is made of stainless steel and has a mesh of 100 mesh (mesh size of 140 μm) and a diagonal length of 15 mm × 1.
5 mm diamond-shaped openings (area = 1.1 m ² ) provided in a staggered arrangement at 18 mm intervals (opening ratio = 69.4%)
It was used. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 1 Fineness: 1.5 denier, fiber length: 7 mm, L / D: 59
No. 4 30% rayon fiber and unbeaten softwood bleached kraft pulp (Canada standard freeness: 690 ml CSF) 70%
The mixture was used as a raw material to form a web in an inclined wire paper machine and then dried to obtain a nonwoven fabric made of rayon and pulp having a basis weight of 50 g / m ² .

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was placed on the non-woven fabric. Using a high-pressure water jet flow treatment apparatus in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 55 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy applied to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.33 kWh / kg. The high-pressure water jet flow shielding plate is a stainless steel 100 mesh wire mesh (aperture 140 μm) with circular openings (area = 3.1 cm ² ) having a diameter of 20 mm provided in a staggered arrangement at 49 mm intervals (opening ratio: 40.0%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 2 A web was formed by wet papermaking using a raw material similar to that used in Example 5 in an inclined wire paper machine, followed by drying.
A non-woven fabric of 0 g / m ² of rayon and pulp was obtained.

The nonwoven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was set on the nonwoven fabric. Using a high-pressure water jet flow treatment apparatus in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 50 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.29 kWh / kg. The high-pressure water jet flow shielding plate is a stainless steel 100-mesh wire mesh (aperture 140 μm) in which circular openings (area = 0.1 cm ² ) having a diameter of 3.5 mm are provided at intervals of 7 mm in a staggered arrangement ( The aperture ratio was 39.2%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 3 In the same manner as in Example 1, a web was formed by wet papermaking on an inclined wire paper machine to form a web, followed by drying and a basis weight of 50 g / m.
^A non-woven fabric consisting of rayon and pulp was obtained. This non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate is placed on the non-woven fabric, and the non-woven fabric is transferred at a speed of 20 m / min.
Using a high-pressure water jet processing apparatus in which nozzle holes of 1.0 mm are arranged at 1.0 mm intervals in two rows in the sheet flow direction, a pressure of 55 kg / cm ² from the top of the nonwoven fabric is used. A high-pressure water jet was jetted at a water pressure, and then dried to obtain a water-disintegratable nonwoven fabric.

The additional specific energy applied to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.33 kWh / kg. The high-pressure water jet flow shielding plate is made of stainless steel and has a 100-mesh wire mesh (mesh size of 140 μm) and circular openings of 14 mm in diameter (area = 1.5 m ² ) provided in a staggered arrangement at 38 mm intervals (opening ratio). = 21.3%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 4 In the same manner as in Example 1, a web was formed by wet papermaking on an inclined wire type paper machine, followed by drying and drying, and a basis weight of 50 g / m2.
^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire mesh, and a high-pressure water jet flow shielding plate was set on the non-woven fabric. Using a high-pressure water jet flow treatment device in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 50 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.29 kWh / kg. The high-pressure water jet flow shield plate was provided with a diamond-shaped opening (area = 1.1 m ² ) having a diagonal length of 15 mm at intervals of 16 mm in a staggered arrangement on a 100-mesh metal mesh (aperture 140 μm) made of stainless steel. (Opening ratio = 87.9%) was used. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 5 Fineness: 1.5 denier, fiber length: 10 mm, L / D: 8
49% rayon fiber 40% and unbeaten softwood bleached kraft pulp (Canada standard freeness: 690ml CSF) 60
% As a raw material, a web was formed on an inclined wire paper machine, and then dried to obtain a nonwoven fabric made of rayon and pulp having a basis weight of 50 g / m ² .

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was placed on the non-woven fabric. Using a high-pressure water jet flow treatment apparatus in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 30 kg / cm ² from the top of the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric.

The specific energy imparted to the nonwoven fabric through the opening of the high-pressure water jet flow shielding plate by this high-pressure water jet flow treatment was 0.05 kWh / kg. The high-pressure water jet flow shield plate is a stainless steel 100 mesh wire mesh (aperture 140 μm) with circular openings (area = 0.5 cm ² ) having a diameter of 8 mm provided at intervals of 14 mm (opening ratio = 51. 3%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Comparative Example 6 Fineness: 1.5 denier, fiber length: 7 mm, L / D: 59
Using a 5% rayon fiber of No. 4 and 95% of unbeaten softwood bleached kraft pulp (Canada standard freeness: 690 ml) as raw materials, forming a wet papermaking web using an inclined wire paper machine, followed by drying and drying A nonwoven fabric consisting of rayon and pulp in an amount of 50 g / m ² was obtained.

This non-woven fabric was placed on a transfer support net formed of a 50-mesh wire net, and a high-pressure water jet flow shielding plate was set on the non-woven fabric. Using a high-pressure water jet flow treatment device in which .15 mm nozzle holes are arranged at 1.0 mm intervals in two rows in the sheet flow direction, 50 kg / cm ² from above the nonwoven fabric. A high-pressure water jet was jetted at a water pressure of, and then dried to obtain a water-disintegratable nonwoven fabric. The additional specific energy imparted to the nonwoven fabric through the opening of the high pressure water jet flow shielding plate by this high pressure water jet flow treatment was 0.29 kWh / kg. The high-pressure water jet flow shield plate is a stainless steel 100 mesh wire mesh (aperture 140 μm) in which circular openings (area = 1.5 cm ² ) having a diameter of 14 mm are provided in a staggered arrangement at 23 mm intervals (opening ratio). = 58.2%). The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 1 shows the results.

Example 8 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio of diameter to fiber length L / D of 594
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

The nonwoven fabric was placed on a transfer support net formed of a 50-mesh wire net, and was transferred at a speed of 30 m / min. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure is 40kg / cm
² , and a partially-perforated high-pressure water jet flow treatment device has a perforated area having a width of 12 mm and a non-perforated area having a width of 5 mm in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 55kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partially opened nozzle by this high-pressure water jet flow treatment was 0.18 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.07 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Example 9 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio of diameter to fiber length L / D of 594
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

The nonwoven fabric is placed on a transfer support net formed of a 50-mesh wire net, and is transported at a speed of 40 m / min. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure is 40kg / cm
² , and the partially-perforated high-pressure water jet flow treatment device has a 7-mm wide aperture area and a 6-mm non-perforated area in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 55 kg / cm ²
Met. The additional specific energy applied to the nonwoven fabric in the opening area of the partial aperture nozzle by this high-pressure water jet flow treatment was 0.13 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.05 kWh. / Kg. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Example 10 The fineness was 3.0 denier, the fiber length was 5 mm, and the L / D was 30.
50% rayon fiber and softwood bleached kraft pulp in Canadian standard freeness 600ml using laboratory beater
Using a mixture of 50% pulp beaten to CSF as a raw material, a web was formed in a tilted wire paper machine and then dried to obtain a nonwoven fabric consisting of rayon and pulp having a basis weight of 65 g / m ² .

This non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and while being transported at a speed of 30 m / min, a partially open high pressure water jet flow treatment device and a full open high pressure water jet Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Using nozzles arranged at intervals, water pressure is 45 kg / cm
² , and the partially-perforated high-pressure water jet flow treatment apparatus has an aperture area of 16 mm width and a non-perforation area of 4 mm width in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 55kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partial aperture nozzle by this high-pressure water jet treatment is 0.15 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area is 0.06 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Example 11 The fineness was 1.5 denier, the fiber length was 10 mm, and the L / D was 8
Using a mixture of 49% rayon fiber 20% and unbeaten softwood bleached kraft pulp (Canadian standard freeness: 680 ml CSF) as a raw material, a web is formed on an inclined wire-type paper machine, and then dried, and the basis weight is 40 g / m ^2. Of non-woven fabric consisting of rayon and pulp.

The nonwoven fabric was placed on a transfer support net formed of a 80-mesh wire net, and was transported at a speed of 50 m / min. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Using nozzles arranged at intervals, water pressure is 60 kg / cm
² , and the partially-perforated high-pressure water jet flow treatment device has an aperture area of 10 mm width and a non-perforation area of 8 mm width in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 70kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partial aperture nozzle by this high pressure water jet flow treatment was 0.21 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.09 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Comparative Example 7 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio L / D of diameter to fiber length of 594 was used.
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

The non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and is transferred at a speed of 30 m / min. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure is 40kg / cm
² , and the partially-perforated high-pressure water jet flow treatment device has a perforated region having a width of 12 mm and a non-perforated region having a width of 2 mm in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 55kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partially opened nozzle by this high-pressure water jet flow treatment was 0.18 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.07 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Comparative Example 8 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio L / D of diameter to fiber length of 594 was used.
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and while being transported at a speed of 30 m / min, a partially open high-pressure water jet flow treatment device and a fully open high-pressure water jet Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure is 40kg / cm
² , and the partially-perforated high-pressure water jet flow treatment device has a 35-mm wide aperture region in which nozzle holes of 0.15 mm diameter are arranged at 1.0 mm intervals and a non-perforated region of 5 mm width are alternately arranged. Water nozzle is 55kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partially opened nozzle by this high-pressure water jet flow treatment was 0.18 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.07 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Comparative Example 9 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio of diameter to fiber length L / D of 594
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

The nonwoven fabric was placed on a transfer support net formed of a 50-mesh wire net, and while being transported at a speed of 30 m / min, a partially open high-pressure water jet flow treatment device and a fully open high-pressure water jet were used. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure is 40kg / cm
^In addition, the partially perforated high-pressure water jet flow treatment device has an aperture area of 8 mm width and a non-perforated area of 15 mm width in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 55kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partially opened nozzle by this high-pressure water jet flow treatment was 0.18 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.07 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Comparative Example 10 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm and a ratio L / D of the fiber length to the fiber length L / D of 594.
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and while being transferred at a speed of 20 m / min, a partially open high-pressure water jet flow treatment device and a fully open high-pressure water jet Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Using nozzles arranged at intervals, water pressure is 50 kg / cm
² , and a partially-perforated high-pressure water jet flow treatment device has a perforated area having a width of 12 mm and a non-perforated area having a width of 5 mm in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 50kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partial aperture nozzle by this high-pressure water jet flow treatment was 0.29 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.14 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

Comparative Example 11 30% rayon fiber having a fineness of 1.5 denier, a fiber length of 7 mm, and a ratio of diameter to fiber length L / D of 594
From a mixture of unbeaten softwood bleached kraft pulp (Canadian standard freeness: 690 ml CSF) as a raw material, wet-paper-making on an inclined wire-type paper machine to form a web, then drying and drying, and a basis weight of 50 g / m ^A non-woven fabric consisting of rayon and pulp was obtained.

This non-woven fabric is placed on a transfer support net formed of a 50-mesh wire net, and while being transported at a speed of 30 m / min, a partially open high-pressure water jet flow treatment device and a full-open high pressure water jet are used. Using a jet flow treatment device, a high-pressure water jet was jetted from above the nonwoven fabric, and then dried to obtain a water-disintegrable nonwoven fabric. At this time, the full-hole type high-pressure water jet flow treatment apparatus has a nozzle hole having a diameter of 0.15 mm of 1.0 mm.
Use nozzles arranged at intervals, water pressure 20kg / cm
² , and a partially-perforated high-pressure water jet flow treatment device has a perforated area having a width of 12 mm and a non-perforated area having a width of 5 mm in which nozzle holes having a diameter of 0.15 mm are arranged at 1.0 mm intervals. Water nozzle is 30kg / cm
^{Was 2} . The additional specific energy applied to the nonwoven fabric in the opening area of the partial aperture nozzle by this high pressure water jet flow treatment was 0.07 kWh / kg, and the additional specific energy applied to the nonwoven fabric in the non-opening area was 0.02 kWh. / Kg
Met. The quality of the obtained water-disintegratable nonwoven fabric was evaluated by the same evaluation method as in Example 1. Table 2 shows the results.

[0114]

[Table 1]

[0115]

[Table 2]

As can be seen from Tables 1 and 2, the nonwoven fabric of the present invention has an excellent balance between wet tensile strength and water disintegration, has a good feel, and has excellent properties as a water disintegratable nonwoven fabric. On the other hand, as can be seen from Table 1, when the area per one opening of the high-pressure water jet flow shielding plate is too large (Comparative Example 1), the easily water-disintegrable region quickly disintegrates into a fibrous form, It easily divides into a 3.1 cm ² quasi-water-disintegrable region, but since the area per one of the quasi-water-disintegrable regions is too large, it takes time until the quasi-water-disintegrable region is further divided into smaller pieces. The result was inferior. When the area per opening of the high-pressure water jet flow shielding plate is too small (Comparative Example 2), the area per quasi-water dissolvable region obtained is too small, and the quasi-water dissolvable region has strength. Is not sufficiently provided, so that only a sheet having low strength can be obtained.

Further, the fiber entanglement imparted to the web in the portion corresponding to the opening of the high pressure water jet flow shielding plate is insufficient, resulting in a poor feeling. When the opening ratio of the high-pressure water jet flow shielding plate is too low (Comparative Example 3), the ratio of the easily water-disintegrable region formed in the obtained water-disintegrable nonwoven fabric to the entire nonwoven fabric becomes too high, and the strength of the sheet is low. turn into. When the aperture ratio of the high-pressure water jet flow shielding plate is too high, the ratio of the easily water-disintegrable region to the entire nonwoven fabric becomes too low. Also, at this time, the area of the quasi-water disintegration region formed was larger than the area corresponding to the opening of the high-pressure water jet flow shielding plate. Due to being too high, the width of the non-opening existing between the openings is too narrow, and the quasi-water dissolvable regions formed in the portions corresponding to the individual openings are completely separated one by one. Probably because there was no.

The water-disintegratable nonwoven fabric also had poor water-disintegrability because the area of each of the finally formed quasi-water-disintegrable regions was too high, and the individual water-disintegrable regions were too small. If the additional specific energy during the high-pressure water jet flow treatment is too low (Comparative Example 5), sufficient entanglement cannot be imparted to the web located at the opening of the high-pressure water jet flow shielding plate, and a quasi-water dissolvable region is formed Could not. For this reason, the strength of the obtained water-disintegratable nonwoven fabric was very weak. When the proportion of the regenerated cellulose fiber constituting the water-disintegratable nonwoven fabric was too small (Comparative Example 6), the strength was not sufficiently developed by the high-pressure jet flow treatment, and only a sheet having low strength was obtained.

Further, as shown in Table 2, when the width of the easily water-dissolvable region was too small (Comparative Example 7), the easily water-disintegrable region was too narrow to disintegrate quickly, and Is too large (Comparative Example 8), it takes a long time to disintegrate after stripping in strips because the width of the strip is too large. Further, when the proportion of the easily water-disintegrable region is large (Comparative Example 9), since the region of strong fiber entanglement affecting the longitudinal strength of the nonwoven fabric is small, the longitudinal strength of the nonwoven fabric is weak, and post-processing to wet tissue or the like is performed. The suitability is poor.

When the added specific energy in the treatment with the high-pressure water jet stream is too large (Comparative Example 10), the fiber entanglement becomes too strong, resulting in poor water dissolvability. On the other hand, when the addition specific energy is too small (Comparative Example 11), the fiber entanglement is not sufficiently obtained, the wet tensile strength is low, the wet tensile strength and the water disintegration are not balanced, and both can be put to practical use. Can not.

[0121]

Industrial Applicability The present invention reduces the content of expensive regenerated cellulose fiber, maintains strength enough to withstand operations such as cleaning in a dry state and a wet state, and forms a nonwoven fabric in a large amount of water flow. The present invention has the effect of providing a water-disintegratable nonwoven fabric whose constituent fibers can be easily disintegrated and a method for producing the same.

[0122]

[Brief description of the drawings]

FIG. 1 is a schematic model diagram showing an example of a water-disintegrable nonwoven fabric manufacturing apparatus according to Examples 1 to 7 and Comparative Examples 1 to 6.

FIG. 2 is a schematic model diagram showing an example of a method for producing a water-disintegratable nonwoven fabric according to Examples 8 to 11 and Comparative Examples 7 to 11.

[0123]

[Explanation of symbols]

1: high-pressure water jet flow shielding plate 2: high-pressure water jet flow generator 3: support for high-pressure water jet flow treatment device 4: water-disintegratable nonwoven fabric 5: high-pressure water jet flow generator equipped with a partially apertured nozzle 6: High-pressure water jet flow generator equipped with a fully-open nozzle 7: Non-open area of partially open nozzle 8: Open area of partially-open nozzle 9: Open area of high-pressure water jet flow shield 10: High pressure Non-open area of water jet flow shield

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // A61F 13/54 A41B 13/02 E

Claims (6)

[Claims] 1. A water-disintegratable non-woven fabric in which regenerated cellulose fibers and wood pulp are entangled and integrated, wherein the non-woven fabric comprises 15 to 55% by weight of regenerated cellulose fibers and 85 to 4 wood pulp.
When the nonwoven fabric having a size of 5 cm × 5 cm (25 cm ² ) composed of 5% by weight is put into 100 ml of pure water and shaken at a shaking speed of 300 cycles / minute and disintegrated in water, a fibrous material is formed. The easily water-disintegrable region that disintegrates into, and the quasi-water-disintegrable region that is relatively difficult to disintegrate in a fibrous form compared to the easily disintegratable region are distributed throughout the nonwoven fabric, and the easily disintegratable region in the nonwoven fabric Is 15% to 70%. 2. The quasi-water-disintegrable region is surrounded by the easily water-disintegrable region, and the area per one of the quasi-water-disintegrable regions is 0.
2 cm ² 2 cm ² of claim 1 wherein the water-decomposable non-woven fabric, characterized in that. 3. A regenerated cellulose fiber of 15 to 55% by weight.
And 85 to 45% by weight of wood pulp, and a web formed by a wet papermaking method is subjected to high-pressure water jet treatment on a perforated support to entangle and integrate the regenerated cellulose fibers and wood pulp. In the method for producing a water-disintegratable nonwoven fabric,
A high-pressure water jet flow shielding plate is installed between the web and the high-pressure water jet flow generator, and high-pressure water jet flow treatment is performed from the upper surface of the high-pressure water jet flow shielding plate toward the web. A non-opening that can shield all or part of the energy imparted to the web by the high-pressure water jet stream before the jet stream reaches the web, and an aperture that can directly apply energy to the web without shielding any energy 3. The method according to claim 1, further comprising:
A method for producing the water-disintegratable nonwoven fabric according to the above. 4. An easily water-disintegrable region that disintegrates in a fibrous form when disintegrated in water and a quasi-water disintegrable region that is difficult to disintegrate in a fibrous shape are alternately distributed over the entire nonwoven fabric and occupy in the nonwoven fabric. The water-disintegratable nonwoven fabric according to claim 1, wherein the proportion of the water-disintegrable region is 15 to 60%. 5. The water-disintegratable nonwoven fabric according to claim 3, wherein the width of the water-disintegrable region is 3 to 15 mm. 6. A regenerated cellulose fiber of 15 to 55% by weight.
And 85 to 45% by weight of wood pulp, and a web formed by a wet papermaking method is subjected to high-pressure water jet treatment on a perforated support to entangle and integrate the regenerated cellulose fibers and wood pulp. In the method for producing a water-disintegratable nonwoven fabric,
The high-pressure water jet flow treatment is performed by combining two or more high-pressure water jet flow generators having different nozzle hole arrangements in one or more rows so as to be parallel to the web width direction. For producing a water-disintegratable nonwoven fabric.