JPH0978423A - Production of paper or nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain paper or a nonwoven fabric having high surface strength and generating little powdery paper by compressing a web added with a binder to the width direction and forming a concentration gradient of the binder in the width direction after relaxing the pressure. SOLUTION: This production method of paper or a nonwoven fabric is to add a binder 17 comprising a foamy liquid of a self-crosslinkable acrylic resin, etc., to a web 12 having >=30% compressive recovery, compress the web 12 in the width direction with >=0.2 compression rate by two rollers 14 and 16 having the same or different contact angle against the binder solution 17, then relax the pressure and form a concentration gradient of the binder in the width direction of the web 12, succeedingly dry and heat treat the web 12 by a drying means 18 and obtain paper or the nonwoven fabric having the concentration gradient of the binder 17 in the width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a paper or a non-woven fabric to which a binder is applied, and more specifically, by controlling the distribution state of the binder in the thickness direction of the sheet material, the thickness direction of the sheet material is controlled. The present invention relates to a method for producing paper or non-woven fabric in which a binder concentration gradient is formed.

[0002]

2. Description of the Related Art
As a method for obtaining a sheet-shaped paper or non-woven fabric (hereinafter, also referred to as “paper and / or non-woven fabric” as a sheet or sheet-like material) in which a binder is applied to a web, after mixing a binder with a cotton-like web in advance, A method in which the web is dried and cured and then heat-melted to form a sheet, a method in which fibrous cotton is manufactured into a web and then impregnated with a binder, a spray coating method or a floss coating method. A method is known in which a web is coated with a binder by a coating method such as a construction method, followed by drying, curing, and heat melting. These methods are intended to uniformly apply the binder to the sheet, and it is difficult to control the distribution state of the binder in the thickness direction of the sheet.

Further, in the above method, even when it is desired to use a binder to exert some function on one side of the sheet, the binder is uniformly applied in the thickness direction of the sheet, and a specific amount of the binder is used with a limited amount of the binder. It could not be expressed, and it was impossible to apply a large amount of binder only to a desired portion, for example, one side.

Therefore, an object of the present invention is to produce a paper or non-woven fabric in which a binder concentration gradient is formed in the thickness direction of a sheet by controlling the distribution of binder components in the thickness direction of the sheet. To provide.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that after applying a binder to a specific web, the web is compressed to a specific compression ratio and then decompressed. It was found that the above object can be achieved by producing paper or nonwoven fabric.

The present invention has been made on the basis of the above findings, and after applying a binder to a web having a compression recovery rate of 30% or more, the web has a compression ratio of 0.2 or more in the thickness direction. The present invention provides a method for producing paper or non-woven fabric, which comprises forming a concentration gradient of the binder in the web in the thickness direction by compressing and then depressurizing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing paper or nonwoven fabric of the present invention will be described in detail below. The method for producing a paper or non-woven fabric of the present invention is a method in which a binder is applied to a specific web, and then the web is compressed in the thickness direction so as to have a specific compression ratio, and then decompressed to give a thickness in the web. Forming a binder concentration gradient in the direction.

The binder used in the present invention is not particularly limited, but conventionally known binders can be used. As the binder, for example, an emulsion or a polymer solution obtained by polymerizing a polymerizable unsaturated monomer (for example, emulsion polymerization or solution polymerization described below) can be used.

The polymerizable unsaturated monomer is not particularly limited, but is, for example, a methylol group such as n-monomethylol acrylamide or n-monomethylol methacrylamide; acrylic acid, methacrylic acid, maleic acid,
Carboxyl groups such as fumaric acid, crotonic acid and itaconic acid; hydroxyl groups such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; epoxy groups such as glycidyl acrylate and glycidyl methacrylate A polymerizable unsaturated monomer having: n-butoxymethyl acrylamide, n-butoxymethyl methacryl, which is a compound obtained by etherifying the methylol group of the above n-monomethylol acrylamide, n-monomethylol methacrylamide with butanol, isobutanol or the like. Acrylamide, isobutoxymethylacrylamide, isobutoxymethylmethacrylamide, etc .; Acrylamide, etc .; methylacrylate, methylmethacrylate, ethylacetate Relate, ethyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, iso-butyl acrylate, iso-butyl methacrylate, n-amyl acrylate, n-amyl methacrylate, iso-amyl acrylate , Iso-amyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl methacrylate, decyl acrylate, decyl methacrylate, dodecyl acrylate, dodecyl methacrylate, Octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl Le methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, acrylic acid ester derivatives such as benzyl methacrylate and methacrylic acid ester derivatives; vinyl acetate, vinyl esters such as vinyl propionate and the like; styrene, vinyl toluene, 2
-Aromatic vinyls such as methylstyrene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene and divinylbenzene; acrylamide, methacrylamide, n-monoethylacrylamide, n-monoethylmethacrylamide, dimethylacrylamide,
Amides such as dimethylmethacrylamide, t-butylacrylamide, t-butylmethacrylamide, diacetoneacrylamide; divinylbenzene, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, polyethylene glycol diacrylate, Polyfunctional monomers such as polyethylene glycol dimethacrylate; acrylonitrile, methacrylonitrile and the like. In the present invention, the polymerizable unsaturated monomer may be used alone or in combination of two or more kinds.

The above emulsion can be synthesized by a known emulsion polymerization method. For example, it can be synthesized by dropping the polymerizable unsaturated monomer into an appropriate amount of water containing a small amount of an emulsifier and a polymerization initiator, and emulsion-polymerizing the polymerizable unsaturated monomer.

The emulsifier is not particularly limited, and examples thereof include general anionic surfactants, cationic surfactants and nonionic surfactants.

The polymerization initiator is not particularly limited,
For example, cumene hydroperoxide, hydroperoxides such as diisopropylbenzene hydroperoxide, benzoyl peroxide, peroxides such as lauroyl peroxide, organic polymerization initiators such as azo compounds such as azobisisobutyronitrile, In addition, inorganic polymerization initiators such as persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate and the like can be mentioned. These polymerization initiators can be used alone or in combination of two or more kinds. Further, a so-called redox polymerization initiator using a reducing agent such as sodium bisulfite, ascorbic acid or a salt thereof in combination with a polymerization initiator can also be used.

In the above emulsion polymerization, a chain transfer agent usually used in emulsion polymerization, n-dodecyl mercaptan, t-dodecyl mercaptan, etc. may be used as necessary.

The proportion of solids in the emulsion thus obtained is generally 3 to 50% by weight, preferably 5 to 20% by weight. As binders other than the above, in addition to acrylic emulsion, styrene butadiene rubber (SBR) latex, nitrile butadiene rubber (NBR) latex, ethylene-vinyl acetate (EV)
A) An emulsion, an aqueous solution of polyvinyl alcohol (PVA), sodium carboxymethyl cellulose (CMC), or the like can also be used.

If necessary, various additives such as nonionic surfactants such as polyoxyethylene nonylphenyl ether and anionic surfactants such as sodium dodecyl sulfate are added to such a binder. You can also The amount of these additives added is 0.1 to 5.0% based on the weight of the binder. Further, if necessary, an antistatic agent, an antifungal agent or the like may be added.

In the method for producing paper or nonwoven fabric of the present invention, the amount of the binder used is preferably in the range of 3 to 40% by weight (solid content), more preferably 5 based on the weight of the fibers constituting the paper or nonwoven fabric. ˜30% by weight (solid content). If the amount of the binder used is less than 3% by weight, the strength of the obtained paper or nonwoven fabric is low and it is difficult to withstand use. Further, when the amount of the binder used exceeds 40% by weight, not only the properties of the obtained paper or non-woven fabric are lost but also the texture is deteriorated, so the content is preferably within the above range.

The web used in the present invention has a compression recovery rate of 30% or more, preferably 40% or more. When the compression recovery rate is less than 30%, it becomes difficult to control the distribution state of the binder component in the thickness direction of the paper or nonwoven fabric, which is the object of the present invention, and a binder concentration gradient is formed in the web in the thickness direction. Becomes difficult. In addition, in the present invention, the compression recovery rate means a value represented by the following formula (I).

[0018]

[Equation 1]

The compression recovery rate used in the present invention is 3
The 0% or more web is not particularly limited, but a fibrous web is preferably used. As the above web,
For example, synthetic fibers such as polyethylene, polypropylene, polyester, polystyrene, polyacrylonitrile, polyamide, rayon, polyethylene terephthalate and polyvinyl alcohol, natural fibers such as pulp, crosslinked pulp, cotton and hemp, glass fibers, carbon fibers and rock wool. The thing which consists of an inorganic fiber is mentioned. Further, if the compression recovery rate is 30% or more, a flexible polyurethane foam or the like in which communication holes are formed can be used as the web of the present invention. Further, if necessary, core-sheath type fibers or side-by-side type fibers which are composite fibers using two kinds of fibers having different melting points can be used. These fibers may be used alone or in combination of two or more.

The fibers may be in the form of continuous filaments or staple fibers. When the above fibers are used in the form of staple fibers, it is generally preferable that the fiber length is 0.5 to 5.0 cm. If the fiber length is within this range, the web can be uniformly manufactured.

The fiber diameter of the above fibers is not particularly limited, but it is generally preferably 1.0 to 2.0 denier. When the fiber diameter is within this range, the web can be uniformly manufactured.

The paper or nonwoven fabric obtained by the method for producing a paper or nonwoven fabric of the present invention has a basis weight of generally 15 g / m 2.
^It is preferably ² or more, more preferably 20 g / m ² or more. If the basis weight is less than 15 g / m ² , the shape retention of the paper or nonwoven fabric is poor and it becomes difficult to withstand use.

In the present invention, in order to manufacture the above-mentioned web, the above-mentioned fibers are generally applied to a card machine to form a web, but the method is not limited to such a method, and for example, a spunbond method, a spunlace method or the like may be used. Good.

When a sheet-shaped paper is obtained as the final product, the present invention may be carried out using a web-shaped sheet manufactured by a conventionally known paper manufacturing method. For example, a web-like sheet obtained by disaggregating the above fibers in water using a disintegrator or the like and using an ordinary paper machine can be used.

Thus, in the method for producing a paper or nonwoven fabric of the present invention, after applying the binder to the web, the web is compressed in the thickness direction so that the compression ratio becomes 0.2 or more, and then the web is compressed. By decompressing, a concentration gradient of the binder is formed in the thickness direction of the web.

In the method for producing paper or nonwoven fabric of the present invention, first, the binder is applied to the web. There is no particular limitation on the method of applying the binder to the web,
It can be performed by a commonly used method. As a method of applying the binder to the web, for example,
Examples thereof include a method of spraying an emulsion containing a binder on a web, a method of immersing a web in an emulsion containing a binder to impregnate the web, and a method of applying the binder to the web as a foam liquid. Among these, when the produced sheet-like material is used as a disposable diaper, a member of sanitary material such as a sanitary napkin or household miscellaneous goods such as a paper towel, a binder capable of obtaining a highly flexible sheet-like material is used. A method in which a foamy liquid is applied to the web is preferable.

To form the above-mentioned binder into a foamy liquid,
The binder can be made into a foamy liquid with a general mixer, mixer, forming machine, or the like. When the binder alone has a low foaming property when it is made into a foamy liquid, a surfactant that improves the foaming property may be added to the binder as necessary. There are no particular restrictions on the type or addition amount of this surfactant.

Next, the web to which the binder is applied is compressed in the thickness direction so that the compression ratio becomes 0.2 or more, preferably 0.3 or more. When the compression ratio is less than 0.2, it becomes difficult to control the distribution state of the binder component in the thickness direction of the sheet material which is the object of the present invention, and a binder concentration gradient is formed in the thickness direction of the web. Will be difficult. The method for compressing the web is not particularly limited, and examples thereof include a commonly used press or a method of using a pair of rolls. Among these, a method of compressing the web in the thickness direction by using a pair of rolls that can compress the web in an extremely short time and can inexpensively produce a sheet-like material is preferable.

In the present invention, the compression ratio means a value represented by the following formula (II), and in the method of compressing a web using a pair of rolls described later, the interval between two rolls is It can be changed by changing it. Compression ratio _{= 1- (t 2 / t 1} ) (II) where, t ₁ and t ₂ are as defined above.

The method for compressing the web using the pair of rolls will be described in more detail with reference to FIG. Here, FIG. 1 is a schematic view showing an example of an apparatus 10 for carrying out the method for producing a paper or a nonwoven fabric of the present invention. In the method for producing paper or nonwoven fabric of the present invention, in order to compress the web 12 in the thickness direction so that the compression ratio becomes 0.2 or more, the web 12 is conveyed in the direction of the arrow by rolling the rolls 14 and 16. Meanwhile, the web 12 is passed between the rolls 14 and 16. When this compression is performed, the gap p between the rolls 14 and 16 is set to 80% or less of the thickness of the web, so that the web 12
Is compressed in the thickness direction so that the compression ratio becomes 0.2 or more. Further, as shown in FIG. 1, by placing the binder 17 in the form of a foam liquid between the roll 16 and the web 12, the web 12 is compressed in the thickness direction while applying the binder 17 to the web 12. be able to.

In the method for producing a paper or nonwoven fabric of the present invention, in order to form a binder concentration gradient in the web 12 in the thickness direction, the material of the pair of rolls 14 and 16 is appropriately selected, that is, the present invention. Roll 1 for binder liquid used to apply to web 12 in
This can be performed by adjusting the contact angle of the materials of 4 and 16 (hereinafter, simply referred to as “contact angle”) and controlling the distribution state of the binder in the thickness direction of the sheet-shaped material.

In the paper or nonwoven fabric manufacturing method of the present invention, two rolls 14 and 16 having the same contact angle can be used as the pair of rolls 14 and 16, and two rolls having different contact angles can be used. Book rolls 14, 16 can also be used.

In the method for producing paper or nonwoven fabric of the present invention, when the contact angles of the rolls 14 and 16 are the same, the binder concentration on the surface of the obtained sheet-like material and the binder concentration inside the sheet-like material are adjusted. It can be different. When the contact angle of the roll 14 and the contact angle of the roll 16 are different from each other, the binder concentrations on both surfaces of the obtained sheet material can be different.

For example, as a pair of rolls 14 and 16,
When a roll with a high contact angle coated with Teflon is used for one of them and a roll made of aluminum with a relatively low contact angle is used for the other roll, the binder concentration on the surface of the Teflon coated side is low and the roll made of aluminum is used. A sheet-like material having a high binder concentration on the roll-side surface can be obtained. Further, when Teflon-coated rolls having a high contact angle are used as the pair of rolls 14 and 16, a sheet-like material having a low binder concentration in the surface layer and a high binder concentration inside can be obtained. When a pair of rolls having a low contact angle that is surface-treated with aluminum or chromium is used as the pair of rolls 14 and 16, a sheet-like material having a high binder concentration in the surface layer and a low binder concentration inside can be obtained.

Next, by decompressing the web 12 compressed in the thickness direction so that the compression ratio becomes 0.2 or more,
The distribution state of the binder is controlled in the thickness direction of the web 12 to form a concentration gradient of the binder 17 in the thickness direction of the web 12 to obtain a sheet. The decompression is performed by the web 1 compressed by using the rolls 14 and 16 described above.
2 is released from the rolls 14 and 16 described above.

Next, the depressurized web 12 is passed through a drying means 18 to be dried to remove water or an organic solvent in the binder 17, and the binder 17 is cured to obtain a paper or a nonwoven fabric. As a means for drying the web 12 in the drying means 18, for example, hot air, hot rolls, infrared rays, microwaves, thermal calendering, etc. can be used, but the method is not limited to these. The temperature for curing the binder 17 is generally 110 ° C. or higher.

After the web 12 obtained by curing the binder 17 in this manner is formed into a sheet, the fibers can be heat-melted to further bond the fibers if necessary, and further, if necessary. , Embossing can be applied to further strengthen the bond between fibers. Further, the sheet-like material manufactured in this manner can be wound up by the winding roller 19.

The paper or non-woven fabric produced by the method for producing paper or non-woven fabric of the present invention is useful as a member of sanitary materials such as disposable diapers and sanitary napkins, and household goods such as paper towels for household use. In addition to this, for example, by increasing the binder concentration on the surface of the sheet-like material, it becomes possible to prevent paper dust of the paper and improve the surface strength, and it is possible to improve the strength inside the sheet and the core. It is possible to obtain a sheet-like material having a structure, and by increasing the binder concentration on one surface of the sheet-like material, it becomes possible to express a large number of specific functions on only one surface of the sheet-like material. , An adhesive, a pressure-sensitive adhesive, or an anti-slip agent can be used as a sheet coated on one side in a large amount. It can also be used as a sheet in which a large amount of adhesive or the like is exposed only on one side while maintaining the function of the binder as a whole sheet.

[0039]

The present invention will be described in more detail with reference to the following examples. It goes without saying that the scope of the present invention is not limited to the examples. In the following description, parts represent parts by weight unless otherwise specified.

[Binder Production Example] Water 495 was added to a separable flask equipped with a stirrer, a thermometer and a reflux condenser.
Part and Emar 20C (manufactured by Kao Corporation, solid content 25%) 2
8 parts were charged, the temperature in the flask was raised to 80 ° C. with stirring under a nitrogen atmosphere, and 1.75 parts of ammonium persulfate was added. In advance, 80.4 parts of ethyl acrylate, n-
Butyl acrylate 146.7 parts, acrylonitrile 1
The emulsion prepared by adding 05 parts, 7.5 parts of acrylic acid and 10.5 parts of n-monomethylol acrylamide with stirring was added dropwise to the separable flask over 2 hours to carry out polymerization. Further, aging was carried out at 80 ° C. for 2 hours, and after cooling, a self-crosslinking acrylic emulsion was obtained. (Nonvolatile component 40.5%, PH 3.5).

[Example 1] In the above [Binder production example]
Diluted the binder produced in
8 wt% binder was prepared. This binder
Bubble with a kisa (apparent specific gravity: 0.1 g / ml), 3
Layered rayon web (basis weight 40g / m ², Thickness 0.
6 mm, width 130 mm), coating amount is 9 g / m²become
Device 10 (roll 1 shown in FIG. 1 while applying
4 and the roll 16 have a roll diameter of 180 mm and a roll width of 4
Iron roll coated with Teflon of 00 mm, roll 1
4 and the roll 16 have a distance p of 0.3 mm)
Compress to a reduction ratio of 0.83, then decompress
This allows the binder concentration gradient in the thickness direction of the web.
An arrangement was formed. The web is then heated at 130 ° C. for 10 minutes
Non-woven fabric that is dried and heat treated to bond the fibers of the web
I got Binder for nonwoven fabric obtained in this way
The amount of (dry solid content) applied was 22.
It was 5% by weight. In the non-woven fabric obtained in this way
The amount of binder applied (concentration) and the compression recovery rate of the web
It was measured by the following method. The results are shown in [Table 1]
You. Further, the contact angles of the roll 14 and the roll 16 are
It was measured by the method. The results are shown in [Table 1]. this
The nonwoven fabric thus obtained has a binder concentration inside.
Since it was high, it had high tear strength.

<Application amount (concentration) of binder in the nonwoven fabric
The weight of each of the three pre-dried webs coated with the binder in Example 1 was measured, and the weight before the binder was applied was subtracted from each of the weights to obtain the coating amount (concentration) of the binder. The web on the side in contact with the roll 14 is a, the web on the side in contact with the roll 16 is c,
The web sandwiched between a and c was designated as b. Webs b and c when the coating amount (concentration) in the web a is 100
The coating amount (concentration) weight ratio of was determined.

<Method of measuring compression recovery rate> The thickness of the obtained nonwoven fabric was measured and determined by the above formula (I).

<Measurement Method of Contact Angle of Roll> The contact angles of the rolls 14 and 16 conform to JIS K 6800 and are measured by a droplet method (FACE contact angle meter CA-DT.A type, manufactured by Kyowa Interface Science Co., Ltd.). ).

[Embodiment 2] The compression ratio was set to 0.
A nonwoven fabric was obtained in the same manner as in Example 1 except that the value was 92. The coating amount (concentration) of the binder in the thus obtained nonwoven fabric, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 1]. The nonwoven fabric thus obtained had a high tear strength due to the high binder concentration inside.

[Example 3] As the roll 16, a roll in which a nylon film (manufactured by Toray Industries, Inc.) is attached to the surface of a rubber roll is used, and the distance p between the roll 14 and the roll 16 is p.
Was obtained in the same manner as in Example 1 except that the compression ratio was set to 0.92 by setting the compression ratio to 0.144 mm. The coating amount (concentration) of the binder in the thus obtained nonwoven fabric, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 1]. It was found that the non-woven fabric thus obtained had a higher binder concentration in the portion in contact with the roll 16 (web c) than in the portion in contact with the roll 14 (web a).

[Example 4] As the roll 16, a roll in which an aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) is attached to the surface of a rubber roll is used, and the interval p between the roll 14 and the roll 16 is 0.144 mm. A nonwoven fabric was obtained in the same manner as in Example 1 except that the compression ratio was 0.92. The coating amount (concentration) of the binder in the nonwoven fabric thus obtained, the compression recovery rate of the web, the roll 14 and the roll 16
Was measured in the same manner as in Example 1. The results are shown in [Table 1]. The nonwoven fabric thus obtained had a high binder concentration on the surface on the roll 16 side even by visual observation.

[Embodiment 5] As the rolls 14 and 16, rolls in which aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) is attached to the surface of a rubber roll are used, and the interval p between the rolls 14 and 16 is 0.45 mm. The compression ratio is 0.75
A nonwoven fabric was obtained in the same manner as in Example 1 except that
The coating amount (concentration) of the binder in the thus obtained nonwoven fabric, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 1]. Since the nonwoven fabric thus obtained had a low binder concentration inside the sheet, it was divided into two at the center by applying a strong force.

[Embodiment 6] An iron roll is used as the roll 16, and the interval p between the roll 14 and the roll 16 is 0.36.
mm except that the compression ratio is 0.80.
A nonwoven fabric was obtained in the same manner as in Example 1. The coating amount (concentration) of the binder in the thus obtained nonwoven fabric, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 1].

[Example 7] A web made of polyethylene terephthalate and rayon (weight ratio 50:50) was used as a web, and an aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) was attached to the surface of a rubber roll as a roll 16. Using a roll, the distance p between the roll 14 and the roll 16 is 0.4
A nonwoven fabric was obtained in the same manner as in Example 1 except that the compression ratio was 0.75 by setting the thickness to 5 mm. The coating amount (concentration) of the binder in the nonwoven fabric thus obtained,
The compression recovery rate of the web and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 1].

Example 8 As a web, polyethylene terephthalate and polyethylene (weight ratio 50:50)
A roll made by sticking an aluminum foil (manufactured by Toyo Aluminum Co., Ltd.) to the surface of a rubber roll is used as the roll 16 and is compressed by setting the interval p between the roll 14 and the roll 16 to 0.09 mm. A nonwoven fabric was obtained in the same manner as in Example 1 except that the ratio was 0.95. The coating amount (concentration) of the binder in the nonwoven fabric thus obtained, the compression recovery rate of the web, the roll 14 and the roll 16
Was measured in the same manner as in Example 1. The results are shown in [Table 1].

[Comparative Example 1] A compression ratio of 0.17 was obtained by setting the interval p between the rolls 14 and 16 to be 1.5 mm.
A nonwoven fabric was obtained in the same manner as in Example 1 except that
The coating amount (concentration) of the binder in the nonwoven fabric thus obtained, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 are shown in Table 1.

[0053]

[Table 1]

Example 9 Crosslinked pulp HBA (wafer
3g (manufactured by Zar Co., Ltd.) is suspended in 300 ml of water,
After disintegrating with a sir for 1 minute, use a square handmade paper machine
Basis weight 45g / cm ², Thickness 0.6mm, 25cm square, including
A wet web-like sheet having a water content of 90% was obtained. Next
And the binder produced in the above [Binder Production Example].
Binder with a solid content of 4% by weight
And adjust this binder to the above web-like sheet 3
The amount of coating is 6.8g / m after being stacked.²Painted to be
The device 10 shown in FIG. 1 [roll 14 is low
Teflon coated with a diameter of 60 mm and a roll width of 250 mm
Rolled iron roll with a roll diameter of 60 mm
Aluminum foil with a width of 250 mm (manufactured by Toyo Aluminum Co., Ltd.)
The roll attached to the surface of the roll,
The interval p with the tool 16 is 0.45 mm] and the compression ratio is 0.
By compressing to 75 and then decompressing
Creates a binder concentration gradient in the thickness direction of the web.
did. Then, the web is dried and heated at 130 ° C. for 10 minutes.
After processing, the fibers of the web were bonded to each other to obtain a paper. this
Of the binder (dry solids) on the paper thus obtained
The coating amount was 15.1% by weight based on the weight of the web.
Was.

The amount of paper binder applied (concentration) and the compression recovery rate of the web thus obtained were measured in the same manner as in Example 1. The results are shown in [Table 2]. Further, the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 2].

Example 10 As a web, crosslinked pulp HBA and polyvinyl alcohol fiber (PVA107-
1. Kuraray Co., Ltd.) [weight ratio 95: 5] using a web having a gap p of 0.7 between rolls 14 and 16.
Paper was obtained in the same manner as in Example 9 except that the compression ratio was 0.60 by setting the thickness to 2 mm. The coating amount (concentration) of the binder in the paper thus obtained, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 2].

[Comparative Example 2] As a web, a web made of NBKP (uncrosslinked pulp, softwood) was used, and roll 1 was used.
Paper was obtained in the same manner as in Example 9 except that the interval p between the roll 4 and the roll 16 was set to 1.53 mm to set the compression ratio to 0.15. The coating amount (concentration) of the binder in the paper thus obtained, the compression recovery rate of the web, and the contact angles of the rolls 14 and 16 were measured in the same manner as in Example 1. The results are shown in [Table 2].

[0058]

[Table 2]

As is clear from [Table 1] and [Table 2], the papers or nonwoven fabrics of Examples 1 to 10 have a binder concentration gradient formed in the thickness direction of the sheet.
In addition, the paper or nonwoven fabric of Comparative Examples 1 and 2 is one in which the binder is uniformly applied in the thickness direction of the sheet.

[0060]

According to the method for producing a paper or nonwoven fabric of the present invention, a binder concentration gradient is formed in the thickness direction of the sheet by controlling the distribution state of the binder component in the thickness direction of the sheet. The produced paper or nonwoven fabric can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus for carrying out the method for producing paper or nonwoven fabric of the present invention.

Claims (5)

[Claims] 1. The binder is applied to a web having a compression recovery rate of 30% or more, the web is compressed in the thickness direction so that the compression ratio is 0.2 or more, and then decompressed, whereby A method for producing paper or non-woven fabric, which comprises forming a concentration gradient of the binder in the thickness direction of the web. 2. The web is compressed in the thickness direction by using a pair of rolls.
A method for producing the described paper or nonwoven fabric. 3. The method for producing paper or nonwoven fabric according to claim 2, wherein the pair of rolls are two rolls having the same contact angle with the binder liquid. 4. The method for producing paper or non-woven fabric according to claim 2, wherein the pair of rolls are two rolls having different contact angles with respect to the binder liquid. 5. The method for producing paper or non-woven fabric according to claim 1, wherein the binder is made into a foam liquid and applied to the web.