JP2014101615A - Nonwoven fabric and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric which maintains mechanical properties such as tensile strength and elongation percentage, and also has abundant water-absorbing properties, even though reducing its production cost.SOLUTION: The nonwoven fabric contains a filament fiber web and a composite fiber web having a composite staple fiber and a cellulose fiber which are thermally welded to each other. The filament fiber web and the composite fiber web are entangled.

Description

  The present invention relates to a non-woven fabric and a method for producing the same, and more particularly to a non-woven fabric comprising long fibers, short fibers, and cellulose fibers and having water absorption and a method for producing the same.

  Paper towels, tissue papers, etc. (hereinafter collectively referred to as sanitary paper) are mainly divided into dry and wet ones, all of which require characteristics such as flexibility, tensile strength, water absorption, and surface lubricity. .

  Conventionally, sanitary paper is mainly formed by entanglement of two-layer fiber webs by a water-jet method. As the fiber web, one obtained by carding a plurality of long fibers (filaments) having an average length of 10 mm to 76 mm is used, and these filaments are chemical fibers. Thus, conventional sanitary paper is made only of long fibers made of chemical fibers, but the cost of chemical fibers is relatively high, which hinders the reduction of raw material costs in the manufacture of sanitary paper.

  Patent Document 1 discloses a wet tissue having high toughness. This wet tissue is composed of two wiping layers as outer layers and a water absorption layer sandwiched between them. The wiping layer and the water absorption layer are combined by a press process using a hot roll. Of these, the wiping layer is made of cotton fiber having a length of 1.25 mm to 5 mm, and the water absorption layer is formed by mixing 50 wt% rayon and 50 wt% polypropylene fiber by hot air treatment. However, the rayon used for this water absorption layer is relatively expensive, and the wet tissue produced by the hot air treatment loses its flexibility.

  Under the circumstances as described above, it is a problem for those skilled in the art to provide sanitary paper that has a good flexibility while using a suitable material and that has a low manufacturing cost.

Taiwan registered utility model No. 182129

  The present invention has been proposed in view of the above circumstances, and an object of the present invention is to provide a non-woven fabric having high water absorption while maintaining mechanical properties while suppressing manufacturing costs.

  To achieve the above object, the present invention includes a long fiber web and a composite fiber web having composite short fibers and cellulose fibers that are heat-welded to each other, and the long fiber web, the composite fiber web, Provides a non-woven fabric characterized by being entangled.

  Further, the present invention provides a method for producing the nonwoven fabric as follows: (a) The mixed short fiber and the cellulose fiber are heat-welded to each other by subjecting the mixed fiber having the composite short fiber and the cellulose fiber to air laying and heat treatment. (B) arranging the composite fiber web between two long fiber webs obtained by carding a mixture having a plurality of long fibers, There is also provided a method for producing a nonwoven fabric, characterized in that the nonwoven fabric is produced by performing the treatment.

  According to the nonwoven fabric according to the present invention, not only the long fiber web but also the composite fiber web having the composite short fiber and the cellulose fiber heat-welded with each other, while the manufacturing cost is suppressed, Water absorption is improved while maintaining mechanical properties.

Hereinafter, the present invention will be described in detail with specific embodiments.
The nonwoven fabric according to the present embodiment comprises a long fiber web made of long fibers (filament fibers), composite short fibers (staple fibers) having heat-weldability, and cellulose fibers heat-welded with the composite short fibers. The long fiber web and the composite fiber web are entangled with each other. The long fiber has a length in the range of 10 mm to 76 mm, and the composite short fiber has a length in the range of 1 mm to 10 mm.

The nonwoven fabric according to this embodiment has a basis weight of 20 g / m ^{2 to} 120 g / m ² and a thickness of 0.1 mm to 5 mm, and can be applied to, for example, paper towels, masks / sheets for beauty packs, panty liners, and the like. it can.

Below, each component of the nonwoven fabric in this embodiment is demonstrated in more detail.
[Long fiber]
The long fibers are selected from the group consisting of natural fibers, chemical fibers, or combinations thereof.
Natural fibers include plant fibers, animal fibers, or combinations thereof. Plant fibers may be used singly or in a mixture of multiple types, for example, but not limited to, seed fibers (such as cotton), bast leather fibers (such as cannabis and flax), leaf fibers (such as manila hemp), fruit fibers (Such as eggplant). Animal fibers may be used singly or as a mixture of plural kinds, and examples thereof include wool and silk.

  Chemical fibers include regenerated fibers, semi-synthetic fibers, synthetic fibers, or a combination of these. Recycled fibers may be used alone or as a mixture of a plurality of types, and examples thereof include rayon. Semi-synthetic fibers may be used alone or in combination of a plurality of types, and examples thereof include acetate fibers. Synthetic fibers may be used singly or as a mixture of two or more types. Examples include polyethylene (abbreviation PE), polypropylene (polypropylene: abbreviation PP), polyethylene terephthalate (abbreviation PET), and polyamide (polyamide). Can be mentioned.

The long fibers are preferably selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, rayon, and cotton fibers from the viewpoint of cost reduction among the above materials.
Moreover, it is good that the usage-amount of the said long fiber is 10 wt%-80 wt% with respect to the whole weight of the nonwoven fabric manufactured, and the thickness of the said long fiber is good in the range of 1 denier-6 denier.

[Composite short fiber]
The composite short fiber used in the present invention has a heat-welding property and can be heat-welded with the cellulose fiber. As the composite short fiber and the cellulose fiber are welded in this way, when the water jet treatment is performed in the production process, the water absorption of the nonwoven fabric is reduced due to the cellulose fiber being washed away. The occurrence of wastewater treatment problems can be prevented.

  The composite short fiber used here is polyethylene-polypropylene fiber (PE / PP), polyethylene-polyethylene terephthalate fiber (PET / PP), low temperature polymerized polylactic acid-high temperature polymerized polylactic acid fiber, maleic anhydride modified polyethylene-polypropylene fiber, It is selected from the group consisting of maleic anhydride modified polyethylene-polyethylene terephthalate fibers and combinations thereof. In the following examples, polyethylene-polypropylene fiber was used as the composite short fiber.

  In addition, it is good that the usage rate of the said composite short fiber is 1 wt%-20 wt% with respect to the whole weight of the nonwoven fabric manufactured, and the thickness of the said composite short fiber is in the range of 1 denier-6 denier. Good.

[Cellulose fiber]
The cellulose fiber has a use ratio of 5 wt% to 60 wt% with respect to the total weight of the produced nonwoven fabric, a thickness within the range of 0.1 denier to 10 denier, and a length within the range of 1 mm to 5 mm. Good.
The cellulose fiber may be produced from paper pulp or wood pulp by a conventional method.

Below, the manufacturing method of the nonwoven fabric based on this invention which used each said fiber as a component is demonstrated.
<Nonwoven Fabric Manufacturing Method>
The method for producing a nonwoven fabric according to the present invention includes the following steps.
(A) The composite short fiber and the cellulose fiber are subjected to an air-laying treatment and a heat treatment to a mixed fiber having a composite short fiber having a length in the range of 1 mm to 10 mm and a cellulose fiber. Form a composite fiber web that is heat-welded to each other.
(B) Each of the composite fiber webs formed in the step (a) was obtained by carding a mixture having a plurality of long fibers having a length in the range of 10 mm to 76 mm. A non-woven fabric is produced by placing it between sheets of long fiber webs and then subjecting it to a water-jet treatment.

  In addition, since the composite short fiber, the cellulose fiber, and the long fiber used by the said manufacturing method are each what was mentioned above, luxury is omitted.

  In the said manufacturing method, it is preferable to use what the ratio of the cellulose fiber with respect to the whole weight of the nonwoven fabric manufactured becomes 5 wt%-60 wt% as a mixed fiber in a process (a). Moreover, as a long fiber web in a process (b), it is preferable to use what the ratio of the long fiber with respect to the whole weight of the nonwoven fabric manufactured becomes 10 wt%-80 wt%.

  Note that the air laying process described above is a process in which a mixed fiber web is formed by uniformly dispersing the mixed fiber in the air stream and sucking it into a screen-like object such as a wire mesh using an air stream such as air, as in the prior art. Is the method. The flow rate of the airflow is 100 CCM to 1000 CCM.

The heat treatment described above is a treatment for binding and fixing the composite short fibers and the cellulose short fibers in the mixed fibers, and can be performed using, for example, a conventionally used heating apparatus. The heating temperature is 50 ° C to 180 ° C. The composite fibrous web after processing basis weight ^{5g / m 2 ~100g / m 2} , is treated to a thickness 0.1 mm to 10 mm.

The carding process described above is a process for forming a long fiber web with a plurality of long fibers, and can be performed using a conventional carding apparatus. Long fiber web formed has a basis weight ^{5g / m 2 ~100g / m 2} , it is treated to a thickness 0.1 mm to 10 mm.

The above-described water jet treatment is a treatment in which a high-pressure water stream is jetted onto a long fiber web so that the long fiber web and the composite fiber web are entangled with each other, and can be performed using a conventional water jet device.
Moreover, according to the said manufacturing method, the said series of processes (air laying, heat | fever, carding, water jet) can be performed on one production line.

Below, an Example is given and this invention is disclosed more concretely.
<Example>
Example 1
A plurality of polyethylene-polypropylene short fibers having an average length of 6 mm (usage amount 10 wt%) and paper pulp (usage amount 50 wt%) were mixed to form a mixed fiber. Subsequently, this mixed fiber was subjected to air laying treatment (air flow rate 130 CMM) and heat treatment (temperature 135 ° C.) to form a mixed fiber web.

  Two long fiber webs are obtained by carding a solid (that is, non-hollow) polyethylene terephthalate long fiber (20 wt%) and a plurality of 4T type polyethylene terephthalate long fibers (20 wt%) having an average length of 38 mm. Formed.

  The mixed fiber web is arranged so as to be sandwiched between the two long fiber webs, and subjected to a water jet treatment (water pressure: 50 bar), whereby the mixed fiber web and the long fiber web are entangled. The resulting nonwoven fabric was manufactured.

(Examples 2 to 6 and Comparative Example 1)
The production steps in Examples 2 to 6 are the same as those in Example 1, but the material and the amount of long fibers used, and the amounts of composite short fibers and cellulose fibers are different from those in Example 1. Comparative Example 1 uses only long fibers and does not contain composite short fibers or cellulose fibers. Specific amounts of each component used are shown in Table 1 below.

The items listed below were measured for the nonwoven fabrics produced in Examples 1 to 6 and Comparative Example 1, respectively. The measurement results are shown in Table 1 below.
<Measurement item>
1. Basis weight (Basis weight: g / m ² )
In accordance with ASTM D3776-85, the temperature of the sample is measured using an electronic balance at a temperature of 23 ± 0.5 ° C., a relative humidity of 65 ± 2%, and a general atmospheric pressure. The mass was determined.

2. Tensile strength (Kgf / 25mm)
The nonwoven fabrics obtained in each Example and Comparative Example were cut to prepare samples each having a length of 150 mm and a width of 25.4 mm, and measurement was performed in accordance with ASTM D1117.

3. Growth rate(%)
The nonwoven fabrics obtained in each Example and Comparative Example were cut to prepare samples each having a length of 150 mm and a width of 25.4 mm, and measurement was performed in accordance with ASTM D1117.

4). Water retention rate (%)
The mass (W1) of the nonwoven fabric obtained in each Example and Comparative Example was weighed, and then each nonwoven fabric was placed in a hot air circulating oven and dried by heating at 105 ± 2 ° C. for about 2 hours, then taken out and placed in a dryer. After cooling for 30 minutes, the mass (W2) was measured again. Based on W1 and W2, the water retention rate was determined by the following formula.
Water retention rate (%) = [(W1-W2) / W1] × 100
5. Water absorption rate (%)
It conformed to the measurement method of nonwoven fabric specified in ISO 9073-6: 2000. Melt blown non-woven bags each having a size of 26 cm × 30 cm × 20 cm were prepared and their mass (W1) was measured. Subsequently, the melt blown nonwoven bag was sealed, and each was immersed in pure water for 5 minutes, taken out, placed on a 10 mesh wire net, allowed to drip naturally for 1 minute, and then re-weighted (W2). Weighed.

After measuring the mass (W3) of the nonwoven fabric obtained in each Example and Comparative Example, each was enclosed in the melt blown nonwoven fabric bag to seal the opening. Thereafter, these were immersed in water for 5 minutes, taken out, placed on a 10-mesh wire net, water was dripped for 1 minute, and the mass (W4) was measured again. Based on the above W1 to W4, the water absorption was determined by the following formula.
Water absorption (%) = {[W4-W3- (W2-W1)] / W3} × 100
6). Stiffness (mN-cm)
The nonwoven fabrics obtained in each Example and Comparative Example were cut to prepare test pieces having a length of 250 mm and a width of 25 mm, respectively, and these were left in an environment at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours. In accordance with the tensile strength measurement method of nonwoven fabric specified in 9073-7: 1995 and the specification of ASTM D-1117, it was measured using a cantilever method flexibility tester.

Specifically, the test piece is placed on a horizontal surface of a test table having a horizontal plane and a slope (45 °), the tip is aligned with the boundary between the horizontal plane and the slope, and the tip gradually protrudes toward the slope side. And the moving distance (cm) until the center of the tip comes into contact with the inclined surface, that is, the length sent out is measured. This was measured six times on the front and back surfaces of the specimen collected in the longitudinal direction and the specimen collected in the lateral direction from the sample, and the average value (C, unit cm) was obtained. Asked.
Flexibility (mN-cm) = Weight per unit area (g / m ² ) × C × 10 ⁻³ (Gravity acceleration is 10 / s ² )

  As can be seen from the results in Table 1, according to the present invention, not only long fibers are used, but some of them are replaced with composite short fibers and cellulose fibers. Compared to a nonwoven fabric composed only of fibers, the nonwoven fabric according to the present invention has good rigidity and water absorption while maintaining certain mechanical properties.

  In summary, the nonwoven fabric according to the present invention is formed using not only long fibers but also composite short fibers and cellulose fibers as compared with conventional nonwoven fabrics for sanitary paper formed only with long fibers. Therefore, the high cost resulting from the use of long fibers can be suppressed as in the prior art, and the water absorption is improved while maintaining a certain level of mechanical properties for use as sanitary paper. Moreover, according to the manufacturing method which concerns on this invention, it can also lead to the reduction of manufacturing cost that an air laying process, heat processing, a carding process, and a water jet process can be performed on one production line.

  As mentioned above, although preferable embodiment and the specific example of this invention were described with the comparative example, this invention is not limited to this, A various change is possible in the range which does not deviate from the summary.

  The non-woven fabric according to the present invention maintains mechanical properties while maintaining manufacturing costs and has improved water absorption, so that hygiene such as paper towels, masks and sheets for beauty packs, panty liners, etc. Useful for paper manufacture.

Claims (9)

A long fiber web;
A composite fiber web having composite short fibers and cellulose fibers heat welded together;
Contains
The nonwoven fabric characterized in that the long fiber web and the composite fiber web are entangled. The nonwoven fabric according to claim 1, wherein the long fiber web is made of a material selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, rayon, and cotton fibers. The composite short fiber is composed of polyethylene-polypropylene fiber, polyethylene-polyethylene terephthalate fiber, low-temperature polymerized polylactic acid-high-temperature polymerized polylactic acid fiber, maleic anhydride-modified polyethylene-polypropylene fiber, maleic anhydride-modified polyethylene-polyethylene terephthalate fiber. The nonwoven fabric according to claim 1 or 2, wherein the nonwoven fabric is at least one selected from the group. The ratio of the said cellulose fiber with respect to the whole weight of the said nonwoven fabric is 5 wt%-60 wt%, The nonwoven fabric as described in any one of Claims 1-3 characterized by the above-mentioned. The ratio of the said composite short fiber with respect to the whole weight of the said nonwoven fabric is 1 wt%-20 wt%, The nonwoven fabric as described in any one of Claims 1-4 characterized by the above-mentioned. The length of the said cellulose fiber is 1 mm-5 mm, The nonwoven fabric as described in any one of Claims 1-5 characterized by the above-mentioned. (A) A composite fiber web in which the composite short fiber and the cellulose fiber are heat-welded to each other is formed by subjecting the mixed fiber having the composite short fiber and the cellulose fiber to an air laying treatment and a heat treatment.
(B) The composite fiber web is placed between two long fiber webs obtained by carding a mixture having a plurality of long fibers, and a nonwoven fabric is produced by performing water jet treatment. ,
The manufacturing method of the nonwoven fabric characterized by the above-mentioned. The method for producing a nonwoven fabric according to claim 7, wherein the mixed fiber is one in which a ratio of the cellulose fiber to the total weight of the produced nonwoven fabric is 5 wt% to 60 wt%. The method for producing a nonwoven fabric according to claim 7 or 8, wherein the long fiber web is one having a ratio of the long fibers to 10 wt% to 80 wt% with respect to the total weight of the produced nonwoven fabric.