JP2001049559A - Wet-interlaced nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vegetable fiber pulp-compounded wet-interlaced nonwoven fabric, having soft feeling in dry and wet states, excellent in wiping properties, and having a small rate of dropping-off of the fiber in a production step, and further to provide a production method thereof. SOLUTION: This wet-interlaced nonwoven fabric comprises 10-90 wt.% vegetable fiber pulp having 1000-5,000 average polymerization degree, 90-10 wt.% acrylic splittable staple having at least a split part, and 0-80 wt.% other staples, and the fibers are three-dimensionally interlaced with each other. The method for producing the wet-interlaced nonwoven fabric comprises forming a sheet-like material by wet papermaking of the mixed fibers, and jetting a high-pressure water to the resultant sheet-like material from a nozzle to split at least a part of the acrylic splittable staple and to three-dimensionally interlace the fibers with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wet entangled nonwoven fabric and a method for producing the same.

[0002]

2. Description of the Related Art Cellulose fibers generally used in entangled nonwoven fabrics include rayon short fibers and wood pulp. As an example of a nonwoven fabric using wood pulp, JP-A-3-14692 discloses a three-dimensionally entangled nonwoven fabric layer (A) mainly composed of vegetable fiber pulp and a fiber length of 15 m.
A composite nonwoven fabric in which a nonwoven fabric layer (B) formed by three-dimensionally intermingling short fibers of m or less is laminated is disclosed. In the case of using wood pulp, since the pulp fiber length is too short, the fibers fall out of the net in the papermaking process and the high-pressure hydroentanglement process, and a large amount of pulp is discharged into drainage, which may cause environmental pollution. Further, when the wastewater is recycled, there is a problem that the filter is immediately clogged. Further, the production yield of the nonwoven fabric is low.
The obtained nonwoven fabric is dense but paper-like and lacks texture and volume. Water-based stains can be wiped off with nonwoven fabrics using either rayon short fibers or wood pulp, but oil-based stains are difficult to remove.

[0003] Japanese Patent Publication No. Hei 7-91750 discloses a water-based and oil-based nonwoven fabric having a high stain-removing effect.
It is composed of acrylic microfibers having a longest cross-sectional diameter of 3 μm, and the surface layer is composed of finely divided microfine acrylic synthetic fibers dispersedly entangled. A large number of fibers having a fiber length of 30 mm or more, which are integrally bonded and entangled, are substantially constituted by only entanglement of the fibers without containing a binder, and the fibers in the surface layer portion and the central portion are substantially continuous. An acrylic nonwoven fabric characterized by the above is disclosed. Acrylic non-woven fabrics have poor water retention and water absorption, and therefore have a problem that they have a hard texture when wet with water, and are difficult to use for personal wipers.

As a non-woven fabric for personal use, a spun-lace non-woven fabric made of 100% cotton is commercially available.
This nonwoven fabric has a soft texture, relatively strong strength, and is widely used. However, this nonwoven fabric can also wipe off water-based stains, but it is difficult to remove oil-based stains. Therefore, in order to remove oily stains such as cosmetics using this, it is necessary to impart a surfactant or the like to the cloth, and when the skin is wiped with the surfactant, the surfactant or the like remains on the skin and the sticky feeling is obtained. There is a problem that remains.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-woven fabric which has a soft texture, a voluminous feel, a good texture when wet with water, and a high ability to remove oily stains such as makeup. It is to be. Another object of the present invention is to provide a method for producing a nonwoven fabric, which has a low fiber drop-off rate in the process of producing the nonwoven fabric and can be produced at low cost.

[0006]

That is, according to the present invention, there is provided a plant fiber pulp having an average degree of polymerization of 1,000 to 5,000.
0% by weight, 90 to 10% by weight of acrylic splittable short fibers at least partially split, and 0 to 80% by weight of other short fibers, and the fibers are three-dimensionally entangled with each other. A wet entangled nonwoven fabric characterized by the above.

Another invention is that the average degree of polymerization is 1000
A fiber mixture comprising 10 to 90% by weight of plant fiber pulp of 10 to 90% by weight, 90 to 10% by weight of acrylic splittable short fibers and 0 to 80% by weight of other short fibers is formed into a sheet by wet papermaking. Then, a high-pressure water is sprayed from a nozzle onto the sheet-like material to split at least a part of the acrylic splittable short fiber, and three-dimensionally entangle the fibers with each other. It is.

The plant fiber pulp used in the present invention includes:
Wood pulp, cotton linter pulp, cotton, hemp,
Natural fibers such as wool can be mentioned. The degree of polymerization of these plant fibers is required to be 1000 to 5000, preferably 1500 to 4000, and more preferably,
2000 to 3000. If the degree of polymerization exceeds 5,000, the fiber length becomes longer, dispersibility in the papermaking process becomes worse,
The appearance does not become beautiful. When the degree of polymerization is less than 1000, the fiber length becomes short, the rate of dropping off the fibers in the papermaking and columnar flow steps increases, and the process loss increases. Also,
The obtained nonwoven fabric becomes paper-like and hard.

[0009] The fiber length of the plant fiber pulp in the present invention is defined as "clark Fiber Classificat".
It is preferably 20% by weight or more, more preferably 25% or more, and most preferably 30 to 70% by weight in the ion% on 14 mesh method (hereinafter referred to as CFC method). The CFC method is represented by the weight% of the fiber remaining on the wire mesh when filtered through a 14 mesh wire mesh. CFC is 20
If it is less than 1, the fiber length becomes short, and the process loss becomes large. If the CFC exceeds 70, the fiber length becomes longer,
Dispersibility deteriorates, and the appearance of the obtained nonwoven fabric deteriorates.

The beating degree of the plant fiber in the present invention is 400.
~ 900ml, more preferably 600 ~ 80
0 ml, more preferably 700-800 ml. The degree of beating is CSF (Canadian standard freeness, Canadia)
n Standard Freeness).
When the CSF is less than 400 ml, the fibers are fibrillated, so that microfibrils increase. Therefore, many hydrogen bonds are formed, the structure becomes dense, and the texture of the obtained nonwoven fabric becomes hard. If the CSF exceeds 900, the hydrogen bonding between the fibers decreases, and it becomes difficult to obtain a uniform nonwoven fabric. For example, the cotton linter pulp used in Example 1 described below has a degree of polymerization of 2200 to 258.
Since 0, CSF is 32, and beating degree is 780, and all of the above-mentioned conditions are satisfied, a good nonwoven fabric having a soft feel and a small fiber falling-off rate in the process can be obtained.

[0011] The fiber length, CFC and beating degree CSF are also affected to some extent by the degree of polymerization of the vegetable fiber pulp, but can also be adjusted as appropriate according to the processing conditions of the vegetable fiber pulp in a subsequent step using a beater, a refiner or the like. It is.

At least a part used in the present invention is divided
Acrylic splittable short fibers that are
Fiber and multi-component fiber
A porous fiber, at least a part of which has a fiber diameter of 0.1.
It is divided into ultrafine fibers of 01 to 5 μm. Minute
The fiber diameter of the ultrafine fiber being split is 0.01 to 1 μm
Wiping performance of wet nonwoven fabric, stripping performance, vegetable fiber
It is more preferable from the viewpoint of the effect of suppressing the falling off of pulp of fiber. Before split
The single yarn diameter of the acrylic splittable short fiber is 8 to 25 μm.
Preferably, more preferably 10-20 μm, fiber
When the length is 20 mm or less, the fiber length L (mm) and the single yarn diameter D (μ
m) The ratio L / D is 0.6 to 2.5 × 10 ^ThreeShort fibers are preferred
Good. For example, it is disclosed in JP-A-2-200857.
Has an unspecified shape in the cross section of the fiber
It has many openings, each of which is inside the fiber
Form streaky voids that are approximately parallel along the length of the fiber
Acrylic synthetic fiber that can be easily thinned by high-pressure water treatment.
What is divided can be used suitably.

By using such ultrafine fibers,
The effect of removing stains such as makeup is exhibited. The content of the acrylic splittable short fibers at least partially split is 1
0-90% by weight is required. If it exceeds 90% by weight, the water absorption of the fabric is reduced, and the texture when wet with water becomes hard. When the content is less than 10% by weight, the effect of the ultrafine yarn is reduced, and the wiping performance is reduced. In addition, the dropout rate of plant fibers also increases.

In the present invention, other short fibers may be mixed in addition to the plant fibers and the acrylic splittable short fibers. Examples of other fibers include regenerated cellulose fibers such as rayon and cupra, and synthetic fibers such as polyester, polyamide, polyolefin, and polyurethane fibers. For example, as shown in Example 3 to be described later, 60% of cotton linter pulp, 30% of rayon short fiber, and 10% of acrylic splittable short fiber are mixed to form a sheet, which is subjected to a high-pressure water treatment, followed by three-dimensional processing. The nonwoven fabric produced by entanglement is extremely improved in water absorption and water retention, and has a soft texture. Next, a method for producing the nonwoven fabric of the present invention will be described.

A known method can be used for the papermaking method. For example, by dispersing acrylic splittable short fibers and plant fibers in water to form a slurry, sending this slurry onto a driving net of an inclined fourdrinier machine with a constant volume pump, and dehydrating from the lower surface of the net with a vacuum pump. A uniform sheet can be manufactured. At this time, a factor affecting the dispersion state of the plant fiber pulp in water is the fiber length, and the degree of polymerization is closely related to the fiber length. From the viewpoint of dispersibility, the fiber length is preferably as short as possible. However, if the fiber length is too short, the dropout rate of the fiber in the process increases, and the yield greatly decreases. Therefore, the dispersibility is good,
In addition, a plant fiber pulp having a degree of polymerization of 1,000 to 5,000 is preferable as a plant fiber pulp having a small fiber falling rate.

In the high-pressure water treatment, a high-pressure water stream is jetted from a nozzle onto the papermaking sheet while moving the sheet.
The suction is performed from the lower surface of the sheet to perform a dehydration process. At this time, the nozzle may be moved left and right, rotated, or fixed. The nozzle diameter is, for example, 0.15 mm to 0.25 mm, but is not particularly limited to this. Water pressure is 1-10MP
a is preferred. By this high-pressure water treatment, at least a part of the acrylic splittable short fibers is split, and the fibers are entangled with each other (referred to as entanglement), thereby increasing the strength of the fabric and suppressing the falling off of the vegetable fiber pulp in the high-pressure water treatment step. Is done. That is, it is possible to appropriately adopt a water pressure that exerts such an effect to the maximum.

[0017] The acrylic splittable short fiber also promotes entanglement with the vegetable fiber pulp and plays a role in suppressing the falling off of the vegetable fiber pulp. At that time, if a plant fiber having a short fiber length is used, the plant fiber cannot be retained even by the acrylic splittable short fiber, and the process loss becomes extremely large. Also,
Since the appearance and voluminous feel of the fabric greatly vary depending on the water pressure and the number of times of the high-pressure water treatment, the high-pressure water treatment conditions can be changed depending on the application. That is, the pressure of the high-pressure water is initially low (preferably 0.5 to 2 MPa) in order to suppress the falling rate of the plant fiber and to give a feeling of texture and volume.
It is preferable to take a technique of increasing the pressure (preferably 2 to 10 MPa) at the time of the second treatment, and to further minimize the number of treatments. Furthermore, in order to increase the appearance and volume of the cloth, the lower net can be replaced with a coarser one at the time of high-pressure water treatment, and a cloth with intentionally perforated holes can be created. In this case, the volume is further increased.

The nonwoven fabric according to the present invention is soft and voluminous, has excellent water retention and water absorption, has a soft texture when wet with water, and is excellent in the effect of removing makeup and the like even when water is applied. Therefore, it can be used for persons, various types of objective wipers, cosmetics and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples. Physical properties were measured as follows. Degree of polymerization: The relative viscosity V is calculated by the Oken type relative viscosity method described in JIS-P-8101. Baker's equation (1),

[0020]

(Equation 1)

(However, V: relative viscosity, C: cellulose concentration (g / l), η: ultimate concentration, n = 4) Staudinger's formula (2)

[0022]

(Equation 2)

(Where DP: average degree of polymerization, Km = 5 × 1)
Obtain the degree of polymerization from ^0-4) .

Tensile strength: According to the method described in JIS-L-1096, the maximum strength is measured from a test piece having a width of 2.5 cm and a grip distance of 10 cm, and the strength is shown per cm. Basis weight: Measured according to the method described in JIS-L-1096, 1018. Bending resistance: Measured by the sensing lever method described in JIS-L-1096, 1018. Water absorbency: Measured by the birec method described in JIS-L-1096, 1018. Water retention: A sample of about 10 cm × 10 cm is weighed (D). After being immersed in pure water for 1 hour, it is suspended with a clip for 10 minutes, and then left to measure the weight (W). Water retention rate = (W−D) / D × 100 Dropout rate: Refers to the weight% of linter pulp falling off during the papermaking and columnar flow steps, and is determined as follows.

A sample of about 10 cm × 10 cm is weighed (a). The sample is immersed in DMF for 4 to 5 hours, filtered by suction, dried and weighed (b). a-b
Is the weight of the acrylic fiber, and the weight c when the cotton linter pulp does not fall off in the process is determined from the composition ratio of the raw yarn. Drop-off rate = (c−b) / c × 100 Peeling property: When lipstick was repeatedly applied to the skin 10 times and immediately rubbed off by reciprocation with a sample containing 100% of water, it was completely dropped. The number of times until feeling was counted, and the number was displayed. Therefore, the smaller the number of times the peeling property is, the better the peeling property is.

[0026]

Example 1 Acrylic splittable short fiber having a single fiber fineness of 1.5 d and a fiber length of 12 mm, a polymerization degree of 2400, and a fiber length of C
A cotton linter pulp having a beating degree of 32 and a beating degree of CSF value of 750 was weighed so as to have an absolute dry weight ratio of 50:50, and dispersed in water to obtain a slurry. This slurry was formed into a sheet with an inclined fourdrinier machine to obtain a sheet having a basis weight of about 60 g / m ² . The sheet was jetted with a columnar water stream having a nozzle pressure of 2 MPa and a water pressure of 2 MPa from nozzles having a nozzle diameter of 0.15 mm, a pitch between nozzles of 5 mm, and three rows, thereby intermingling the fibers. The distance between the nozzle and the sheet was 30 mm. A similar treatment was performed on the opposite side of the sheet. Next, a nozzle diameter of 0.15 mm,
Nozzle pitch 5mm, 7.1M from 5 rows of nozzles
Similarly, a columnar flow treatment was performed on both sides at a water pressure of Pa. Table 1 shows the physical properties of the nonwoven fabric thus obtained. This nonwoven fabric had improved water absorption and water retention as compared to the 100% acrylic splittable short fiber product, and exhibited a soft texture.

[0027]

Example 2 Using the same acrylic splittable short fiber and cotton linter pulp as in Example 1, the composition ratio was 90: 1.
Papermaking and columnar flow treatment were performed in the same manner as in Example 1 so as to be 0, 70:30, 30:70, and 10:90. Table 2 shows the physical properties of the obtained nonwoven fabric. By increasing the proportion of the cotton linter, the stiffness and softness of the fabric were reduced, the fabric became softer, and the water retention was further improved.

[0028]

Example 3 Using the same acrylic splittable short fiber and cotton linter pulp as in Example 1, a single fiber fineness of 1.5
(d) A 30% rayon having a fiber length of 8 mm was prepared, adjusted to be 10% acrylic splittable short fiber and 60% cotton linter pulp, and similarly subjected to papermaking and columnar flow treatment to produce a nonwoven fabric. Table 1 shows the physical properties of the obtained nonwoven fabric. By mixing rayon, the water absorption and the water retention were improved.

[0029]

[Comparative Example 1] The physical properties of the nonwoven fabric obtained by subjecting the same non-woven fabric to 100% acrylic splittable short fiber and 100% cotton linter pulp as in Example 1 to papermaking and columnar flow treatment as in Example 1 are shown in Table 1. Show. When the acryl-based splittable short fiber was 100%, the water absorption and the water retention decreased, and the stiffness of the fabric increased. Nonwoven fabric made of 100% cotton linter pulp could not be produced due to insufficient strength. Table 1 shows the physical property data.

[0030]

EXAMPLE 4 The CFC values of three different plant fiber pulps having a degree of polymerization of 1,000, 3,000 and 5,000 were respectively 2
4, 35, 40 and the CSF value were adjusted to a plant fiber pulp in the range of 730 to 750 with a refiner, and the slurry was adjusted so that the composition ratio of the acrylic splittable short fibers used in Example 1 was 50:50. Thereafter, papermaking and columnar flow treatment were performed in the same manner as in Example 1 to produce a nonwoven fabric.

Table 3 shows the physical properties of the obtained nonwoven fabric. According to this table, as the degree of polymerization increases, the falling rate of the fibers decreases.

[0032]

Comparative Example 2 The same acrylic splittable short fiber as in Example 1 was used, the degree of polymerization was 500 and 6000, and the CFC value was 1
6, 72, using a plant fiber pulp having a CSF value of 730 to 750, the composition ratio was adjusted to be 50:50, a fabric was prepared in the same manner as in Example 1, and the physical properties were measured.
Shown in Wood pulp having a degree of polymerization of 500 has a high fiber shedding rate and a high hardness of the fabric. Hemp pulp having a high degree of polymerization of 6000 has a small fiber shedding rate, but has a poor appearance. The texture is also hard.

[0033]

Comparative Example 3 Table 1 shows the results of evaluation of physical properties using a commercially available cotton spunlace nonwoven fabric. The number of times of stripping is twice that of the first embodiment.

[0034]

Example 5 The same acrylic splittable short fibers and cotton linter pulp as in Example 1 were used. By changing the refiner treatment conditions of cotton linter pulp, three types of beating degrees differ, and CSF values are 480, 640, 710,
Using the material adjusted to 910, papermaking and columnar flow treatment were similarly performed to prepare a nonwoven fabric. Table 4 shows the physical properties of the obtained nonwoven fabric.
Shown in Those having a beating degree of 480 show a tendency to have a high degree of bending, and those having a degree of beating of 910 have a low degree of bending.
The appearance of the fabric tends to deteriorate.

[0035]

Example 6 The same acrylic splittable short fibers as in Example 1 and plant fiber pulp with a polymerization of 5,000 were changed in three kinds of fiber lengths by changing the refiner treatment conditions, and CFC values were 22, 26, 38, and 63. The papermaking and the columnar flow treatment were similarly performed to produce a nonwoven fabric. Table 5 shows the physical properties of the obtained wet entangled nonwoven fabric. Those having a small CSF tend to have a high fiber shedding rate. On the other hand, those having a large CSF have a small falling-off rate, but show a tendency that the appearance of the fabric is deteriorated.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

The wet entangled nonwoven fabric of the present invention has a soft feel and a voluminous feel, and exhibits excellent wiping performance for both aqueous and oily stains. In particular, when wetted with water, it has excellent water retention on the fiber surface, so it exhibits a firm swelling feeling and easily removes oily fixed substances such as makeup without the help of surfactants. Have. The production method of the present invention solves the problem of pulp falling off when a large amount of plant fiber pulp is entangled with a high-pressure water stream, and improves the basic unit and the recyclability of high-pressure water, reduces the environmental burden, and is inexpensive. Enables production of wet entangled nonwoven fabric.

Claims (3)

[Claims] 1. A plant fiber pulp having an average degree of polymerization of 1,000 to 5,000 is 10 to 90% by weight, and an acrylic splittable short fiber at least partially divided is 90 to 10% by weight.
And a non-woven fabric comprising 0 to 80% by weight of short fibers other than those described above, wherein the fibers are three-dimensionally entangled with each other. 2. The wet entangled nonwoven fabric according to claim 1, wherein the vegetable fiber pulp is cotton linter pulp. 3. A plant fiber pulp having an average degree of polymerization of 1,000 to 5,000 is 10 to 90% by weight, an acrylic splittable short fiber is 90 to 10% by weight, and other short fibers are 0 to 80%.
After the fiber mixture consisting of wt% is formed into a sheet by a wet papermaking method, high-pressure water is jetted from the nozzle onto the sheet,
A method for producing a wet entangled nonwoven fabric, comprising splitting at least a part of acrylic splittable short fibers and three-dimensionally entangled with each other.