JP4749320B2 - Manufacturing method of composite nonwoven fabric - Google Patents

Description

  The present invention relates to a method for producing a composite nonwoven fabric, and more particularly to a method for producing a composite nonwoven fabric suitable for use as a surface material for absorbent articles such as sanitary napkins and disposable diapers.

  As a prior art regarding the manufacturing method of the sheet | seat used for the surface material etc. of an absorbent article, the technique of the following patent documents 1 and 2 is proposed, for example. The technology described in Patent Document 1 is a technique in which fiber webs opened by a card machine are overlapped and passed between embossing rolls to form a composite, but the obtained nonwoven fabric has a fiber other than the joining part by the embossing rolls. Since it is not heat-sealed, it becomes fuzzy and is not preferable when used as a surface material for absorbent articles. Moreover, the composite nonwoven fabric which consists of the fiber web opened with the card machine is easy to be crushed, and only a thin one can be obtained. The technique described in Patent Document 2 is a technique in which at least two short fiber nonwoven fabrics are bonded together by hot embossing to be combined. Although there is no detailed description regarding the manufacturing method of a short fiber nonwoven fabric in patent document 2, when a short fiber nonwoven fabric is wound once in the manufacturing process and made into a raw fabric, before being wound, Due to its bulkiness, it tends to collapse. Accordingly, a composite of two short fiber nonwoven fabrics bonded by hot embossing is thin, and the texture and flexibility cannot be sufficiently obtained.

  On the other hand, the present applicant has proposed the technique described in Patent Document 3 below. In this technique, a nonwoven fabric is fed from a nonwoven fabric raw material wound in a roll shape, and its bulk is recovered.

Japanese National Patent Publication No. 8-504136 Japanese Patent Laid-Open No. 2005-312601 JP 2004-137655 A

  An object of this invention is to provide the manufacturing method of a composite nonwoven fabric which has an unevenness | corrugation, and is bulky and favorable in texture.

  The present inventors pay attention to the technology described in Patent Document 3 above, and perform bulk recovery treatment on a specific nonwoven fabric, and then partially join with another nonwoven fabric, particularly a bulky nonwoven fabric to form a composite. The present inventors have found that a composite nonwoven fabric that is bulky and has a good texture can be produced, thereby completing the present invention.

  The present invention has been made on the basis of the above knowledge, and a nonwoven fabric produced using a fiber web opened by a card machine as a raw material is unwound from a raw material wound in a roll shape, and heated to restore the bulk. To produce a first nonwoven fabric, and then embossing the first nonwoven fabric and a second nonwoven fabric different from the first nonwoven fabric, and making these nonwoven fabrics uneven A method for producing a composite nonwoven fabric that is integrally bonded and integrated.

  According to the present invention, it is possible to suitably manufacture a composite nonwoven fabric having irregularities, bulky and good texture.

  The present invention will be described below based on preferred embodiments with reference to the drawings.

  As shown in FIG. 1, the manufacturing method of the composite nonwoven fabric of this embodiment pays out the nonwoven fabric 10 manufactured using the fiber web opened by the card machine 2A from the raw fabric 100 wound in the roll shape. The first nonwoven fabric 11 and the second nonwoven fabric 12 different from the first nonwoven fabric 11 are superposed on each other after heating and bulk recovery treatment to produce the first nonwoven fabric 11. Embossing is performed at 31 and 32, and these nonwoven fabrics are partially joined and integrated with unevenness to form a composite nonwoven fabric 1.

  In this embodiment, the nonwoven fabric 10 is manufactured using the fiber web 110 which opened the fiber with the card machine 2A as a raw material. By using a fiber web opened by a card machine as a raw material, various methods can be employed in which a nonwoven fabric having a high bulk and good texture can be obtained in the step of forming the fiber web into a nonwoven fabric. In this case, the fiber length of the fiber web is preferably 100 mm or less, and particularly preferably 80 mm or less. As a method for forming a fibrous web into a nonwoven fabric, an air-through method is preferable from the viewpoint of obtaining a nonwoven fabric that is particularly bulky and has a good texture.

  The heat treatment temperature when the nonwoven fabric 10 is produced by the air-through method is preferably not less than the melting point of the constituent fibers of the nonwoven fabric 10 and less than the melting point + 20 ° C. from the viewpoint of the texture and productivity of the resulting nonwoven fabric. When the nonwoven fabric 10 is composed of a composite fiber (for example, a core-sheath type or a side-by-side type composite fiber), the melting point of the lowest melting point resin constituting the composite fiber is adopted as the melting point of the constituent fiber. .

  Although the fiber which comprises the nonwoven fabric 10 does not have a restriction | limiting in particular, Since it is excellent in bulkiness, it is preferable that it is a composite fiber which has heat-fusion property. In addition, it is preferable that the composite fiber is mechanically crimped because it is excellent in bulkiness. Further, the composite fiber is preferably a core-sheath type or side-by-side type composite fiber made of a thermoplastic resin in order to obtain a nonwoven fabric excellent in bulkiness. Since steric crimp is expressed, it is preferable because it is more bulky.

Examples of the thermoplastic resin constituting the nonwoven fabric 10 include polyester polymers, polyamide polymers, polyolefin polymers, and the like.
Examples of the polyester-based polymer include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and the like, and copolymers thereof. In use, these may be used alone or in combination of two or more. it can.
Examples of polyamide polymers include polyamide polymers such as nylon 6, nylon 66, nylon 2, nylon 3, nylon 4, nylon 7, nylon 11, nylon 12, nylon 610, and copolymers. These can be used alone or in admixture of two or more.
Polyolefin polymers include propylene homopolymer, ethylene-propylene copolymer, ethylene-butene 1-propylene terpolymer, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate. A copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, and the like can be mentioned, and these can be used alone or in combination of two or more.

  When the nonwoven fabric 10 is composed of composite fibers, at least one of the resins constituting the composite fibers uses a polyester-based homopolymer or a polyolefin-based homopolymer from the viewpoint of bulkiness and retention of the uneven structure. It is preferable. Moreover, when the point which is excellent in bulk recovery property is considered, it is preferable that one glass transition point of resin which comprises a composite fiber is room temperature (about 10-30 degreeC) or more. Further, from the viewpoint of the formability and retention of the concavo-convex composite nonwoven fabric, the difference in melting point between the two types of resins constituting the composite fiber is preferably at least 10 ° C or higher, preferably 30 ° C or higher, more preferably 60 ° C or higher. .

  Next, the nonwoven fabric 10 drawn out from the raw fabric 100 wound in a roll shape is heated to perform a bulk recovery process.

  Although there is no restriction | limiting in particular in the heating method of the nonwoven fabric 10 in a bulk recovery process, From a viewpoint of implementing a bulk recovery efficiently, an air through system is preferable. Here, the air-through method is a method in which hot air is blown onto the nonwoven fabric 10 and the blown hot air penetrates the nonwoven fabric 10 to recover the bulk of the nonwoven fabric 10. The temperature of the hot air blown onto the nonwoven fabric 10 is preferable in terms of the bulk recoverability and productivity of the nonwoven fabric obtained by setting the melting point of the constituent fibers of the nonwoven fabric 10 to (minus) 50 ° C. or higher and lower than the melting point. When the nonwoven fabric 10 is composed of a composite fiber (for example, a core-sheath type or a side-by-side type composite fiber), the melting point of the lowest melting point resin constituting the composite fiber is adopted as the melting point of the constituent fiber. .

  When performing the bulk recovery process by the air-through method, the hot air blowing surface is not particularly limited, but it is preferable to blow hot air from the hot air blowing surface 10A side during the production of the nonwoven fabric 10 from the viewpoint of obtaining a bulkier nonwoven fabric.

1.0-10.0 mm is preferable and, as for the thickness of the 1st nonwoven fabric 11 after a bulk recovery process, 1.5-5.0 mm is more preferable. Moreover, 5-60 g / m < ² > is preferable and, as for the basic weight of a 1st nonwoven fabric, 10-30 g / m < ² > is more preferable. The thickness of the first nonwoven fabric 11 after the bulk recovery process is preferably 1.5 to 10 times, more preferably 2 to 5 times that before the bulk recovery process.

  In this embodiment, as shown in FIG. 1, the 2nd nonwoven fabric 12 is manufactured by using the fiber web opened by the card machine 2B as a raw material. By using a fiber web opened by a card machine as a raw material, various methods can be employed in which a nonwoven fabric having a high bulk and good texture can be obtained in the step of forming the fiber web into a nonwoven fabric. In this case, the fiber length of the fiber web is preferably 100 mm or less, and particularly preferably 80 mm or less. As a method for forming a fibrous web into a nonwoven fabric, an air-through method is preferable from the viewpoint of obtaining a nonwoven fabric that is particularly bulky and has a good texture.

  The heat treatment temperature when the second nonwoven fabric 12 is produced by the air-through method is preferably not less than the melting point of the constituent fibers of the second nonwoven fabric 12 and less than the melting point + 20 ° C. from the viewpoint of the texture and productivity of the resulting nonwoven fabric. . When the second nonwoven fabric 12 is composed of a composite fiber (for example, core-sheath type or side-by-side type composite fiber), the melting point of the constituent fiber is the melting point of the lowest melting point resin constituting the composite fiber. Adopted.

  Although the fiber which comprises the 2nd nonwoven fabric 12 does not have a restriction | limiting in particular, Since it is excellent in bulkiness, it is preferable that it is a composite fiber which has heat-fusability. In addition, it is preferable that the composite fiber is mechanically crimped because it is excellent in bulkiness. Further, the composite fiber is preferably a core-sheath type or side-by-side type composite fiber made of a thermoplastic resin in order to obtain a nonwoven fabric excellent in bulkiness. Since steric crimp is expressed, it is preferable because it is more bulky.

Examples of the thermoplastic resin constituting the second nonwoven fabric 12 include a polyester polymer, a polyamide polymer, and a polyolefin polymer.
Examples of the polyester-based polymer include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and the like, and copolymers thereof. In use, these may be used alone or in combination of two or more. it can.
Examples of polyamide polymers include polyamide polymers such as nylon 6, nylon 66, nylon 2, nylon 3, nylon 4, nylon 7, nylon 11, nylon 12, nylon 610, and copolymers. These can be used alone or in admixture of two or more.
Polyolefin polymers include propylene homopolymer, ethylene-propylene copolymer, ethylene-butene 1-propylene terpolymer, high density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate. A copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, and the like can be mentioned, and these can be used alone or in combination of two or more.

1.0-10.0 mm is preferable and, as for the thickness of the 2nd nonwoven fabric 12, 2.0-5.0 mm is more preferable. Moreover, 5-60 g / m < ² > is preferable and the basic weight of the 2nd nonwoven fabric 12 has more preferable 10-30 g / m < ² >.

  In the present embodiment, the first nonwoven fabric 11 and the second nonwoven fabric 12 obtained as described above are overlapped. The fibers constituting the first nonwoven fabric 11 and the second nonwoven fabric may be the same material or different materials.

  In the present embodiment, the first nonwoven fabric 11 is inverted, and the hot air blowing surface 10 </ b> A at the time of manufacturing the nonwoven fabric 10 and the hot air blowing surface 12 </ b> A at the time of manufacturing the second nonwoven fabric 12 are overlapped and joined. Thereby, the texture of the surface of the composite nonwoven fabric 1 obtained can be made more favorable. In particular, when the composite nonwoven fabric 1 is used as a surface material of an absorbent article, a structure in which hot air blowing surfaces at the time of manufacture are overlapped as described above from the viewpoint of fuzz resistance.

  And the laminated nonwoven fabric is pinched by a pair of embossing rolls 31 and 32, and is partially heat-sealed and joined. Of the pair of embossing rolls 31 and 32, the roll 31 is a sculpture roll having a large number of convex portions formed on its peripheral surface. When the first nonwoven fabric 11 and the second nonwoven fabric 12 are joined, the height of the roll 31 is preferably 0.5 mm or more from the viewpoint of expressing a sufficient uneven structure, before embossing. More preferably, the thickness of the first nonwoven fabric 11 and the second nonwoven fabric 12 is greater than the total thickness. On the other hand, the roll 32 is a smooth roll having a smooth peripheral surface. Here, the embossing height refers to the height from the circumferential surface in the normal direction of the convex portion of the embossing roll 31.

  Each roll 31, 32 may be heated to a predetermined temperature, or may not be heated. In the case of heating, the temperature is preferably in the vicinity of the melting point of the resin having the lowest melting point in the constituent fibers of the nonwoven fabrics 11 and 12, from the viewpoint of firmly bonding the joints. Although it depends on the type of fiber, it is preferable that the melting point of the constituent fiber−20 ° C. <the heating temperature of the embossing roll <the melting point of the constituent fiber + 50 ° C.

  The form and arrangement pattern of the joint portion 13 between the first nonwoven fabric 11 and the second nonwoven fabric 12 can be set according to the use of the composite nonwoven fabric, and there is no particular limitation, but as shown in FIG. It is preferably circular in shape and arranged in a dot pattern in a staggered arrangement pattern. It is preferable from the viewpoint of bulkiness, texture, and strength of the composite nonwoven fabric 1 that the joint portions 13 are arranged at a pitch of 1 to 20 mm, particularly 3 to 10 mm.

The composite nonwoven fabric 1 having irregularities thus obtained is bulky and has a good texture. Moreover, since the manufacturing of the composite nonwoven fabric with the above effects does not require significant improvement in the manufacturing facility, it can be manufactured at low cost. Composite nonwoven fabric 1, depending on the application, for example, when using a composite nonwoven fabric 1 as a surface sheet of an absorbent article has a basis weight of ^{10g / m 2 ~120g / m 2} , especially 20g / m ² ~60g / m ² is preferred. Moreover, when using this as a surface sheet of an absorbent article, for example, 1.0-20 mm is preferable and, as for the thickness of the composite nonwoven fabric 1, 2.0-10.0 mm is more preferable.
In particular, from the viewpoint of softness and flexibility of the entire composite nonwoven fabric and low residual property to the sheet such as urine and menstrual blood as a surface sheet, and from the viewpoint of quickly transmitting urine and menstrual blood, the composite nonwoven fabric has a basis weight of 10 to 10%. It is preferable to have a low basis weight of 40 g / m ² and a thickness of 2.0 to 10.0 mm.

  The manufacturing method of the composite nonwoven fabric of this embodiment is applicable as it is to the manufacturing process of an absorbent article. In this case, the composite nonwoven fabric 1 can be continuously supplied to the manufacturing process of the absorbent article as it is, or it can be wound up as a raw material and supplied as a raw material.

  As described above, according to the method for manufacturing a composite nonwoven fabric of this embodiment, the first nonwoven fabric 11 subjected to the bulk recovery treatment and the bulky second nonwoven fabric 12 are partially joined, thereby being bulky. The composite nonwoven fabric 1 having unevenness with a good texture can be produced easily and inexpensively. Moreover, in the manufacturing method of the composite nonwoven fabric of this embodiment, each nonwoven fabric can be selected arbitrarily and various nonwoven fabrics can be manufactured.

  When the composite nonwoven fabric 1 obtained in this way is used as a surface sheet of various absorbent articles such as sanitary napkins, panty liners, and disposable diapers, for example, an absorbent article having a good feel and excellent wearing feeling can be obtained. Can do.

The present invention is not limited to the embodiment.
As in the method for producing a composite nonwoven fabric of the above embodiment, the nonwoven fabric 10 before bulk recovery treatment used for the first nonwoven fabric 11 is a non-woven fabric produced by an air-through method. It is preferable to use a nonwoven fabric that has been recovered in bulk, but if it is manufactured using a fiber web opened by a card machine as a raw material and the bulk of the nonwoven fabric 10 is recovered by a bulk recovery process by heating, a heat roll Nonwoven fabrics manufactured by various nonwoven fabric manufacturing methods such as a method, a spunlace method, a needle punch method, a chemical bond method, an airlaid method, a melt blown method, and a spunbond method can also be used.

  In addition, as in the method for manufacturing a composite nonwoven fabric of the above embodiment, the present invention preferably uses a nonwoven fabric manufactured by spraying hot air on a fiber web opened by a card machine by an air-through method. However, the nonwoven fabric manufactured by heat-bonding the fiber web opened with the card machine by the heat roll system with the other nonwoven fabric can also be used. Further, as shown in FIG. 3, the hot air blowing surface 10A ′ side when the nonwoven fabric 10 ′ is manufactured by unwinding from the raw fabric 100 ′ of the nonwoven fabric 10 ′ manufactured using the fiber web 110 ′ opened by the card machine 2B as a raw material. Thus, a nonwoven fabric that has been subjected to bulk recovery treatment by blowing hot air in the same manner as the first nonwoven fabric described above can also be used as the second nonwoven fabric 12.

  Further, in the present invention, as in the above embodiment, it is preferable to perform heating in the bulk recovery treatment by blowing hot air to the nonwoven fabric by an air-through method, but instead, heating is performed by irradiating far infrared rays. Or, it can be heated by bringing it into contact with a heating source such as a heat roll.

  Moreover, in the said embodiment, although the hot-air blowing surface 10A at the time of manufacture of the 1st nonwoven fabric 11 and the hot-air blowing surface 12A at the time of manufacture of the 2nd nonwoven fabric were overlapped and joined, the direction of a joining surface is, It is not restricted to this, It can select arbitrarily according to a use. The hot air blowing surface of the first nonwoven fabric can be directed outward and bonded to the hot air blowing surface of the second nonwoven fabric, or the back surfaces of the hot air blowing surfaces can be bonded to each other as a bonding surface.

  Hereinafter, the present invention will be described more specifically with reference to examples. This invention is not restrict | limited at all by this Example.

  Two types of nonwoven fabrics shown in Table 1 were used, and composite nonwoven fabrics were produced as in Examples 1 and 2 and Comparative Examples 1 to 3 below. And the thickness, specific volume, and texture of the obtained nonwoven fabric were evaluated as follows. The results are shown in Table 2.

[Example 1]
The nonwoven fabric shown in Table 1 was produced as follows.
<Production of first nonwoven fabric>
Using a fiber web obtained by opening the core-sheath type composite fiber shown in Table 1 with a card machine as a raw material, a nonwoven fabric was produced by an air-through method and wound into a roll to obtain a raw fabric. And the nonwoven fabric was drawn | fed out from this raw fabric, the bulk recovery process shown in Table 1 was given, and it was set as the 1st nonwoven fabric.

<Production of second nonwoven fabric>
Using a fiber web obtained by opening the core-sheath type composite fiber shown in Table 1 with a card machine, a nonwoven fabric was produced by an air-through method.

<Production of composite nonwoven fabric>
The first nonwoven fabric and the second nonwoven fabric produced as described above are overlapped in the orientation of the joining surface shown in Table 2, and between the pair of temperature-embossed rolls (emboss height 1 mm) shown in Table 2. The two nonwoven fabrics were partly joined and integrated with unevenness to obtain a composite nonwoven fabric as shown in FIG.

  The area ratio of the bonded portion per unit area of the obtained composite nonwoven fabric was 12.8%, each bonded portion had a circular shape, and the arrangement pattern thereof was a staggered arrangement as shown in FIG.

[Measurement of thickness]
The thickness of the obtained composite nonwoven fabric was measured using a constant pressure type thickness meter. The pressure at that time was 0.5 g / cm ² .

[Measurement of specific volume]
The specific volume of the obtained composite nonwoven fabric was calculated by the following calculation formula by measuring the thickness obtained by the above thickness measurement and the basis weight of the composite nonwoven fabric.
Specific volume = thickness / basis weight

[Evaluation of texture]
About the obtained composite nonwoven fabric, the degree of softness was evaluated by five monitors. At this time, the average score of five monitors was calculated according to the following evaluation criteria.
Soft: +1
Neither: 0
Not soft: -1

[Example 2 and Comparative Examples 1 and 2]
A composite nonwoven fabric was produced in the same manner as in Example 1 except that the nonwoven fabric shown in Table 1 was used and joined under the joining conditions shown in Table 2, and the thickness / specific volume and texture were evaluated.

[Comparative Example 3]
A composite nonwoven fabric was prepared in the same manner as in Example 1 except that the card web shown in Table 1 was used and the joining was performed under the joining conditions shown in Table 2, and the thickness, specific volume and texture were evaluated.

As shown in Table 2, since the composite nonwoven fabrics of Examples 1 and 2 are subjected to bulk recovery treatment on the first nonwoven fabric, the composite nonwoven fabrics of Comparative Examples 1 to 3 are thicker and have a larger specific volume. I understood it. In particular, in the composite nonwoven fabric of Example 1 and Comparative Example 1 using nonwoven fabrics having a low basis weight (10 g / m ² ), the effect of bulk recovery becomes clearer, and the composite nonwoven fabric is subjected to bulk recovery treatment. It was found that there was a large difference in unevenness between the case of the applied Example 1 and the case of Comparative Example 1 where the bulk was not recovered. Moreover, since the composite nonwoven fabric of the Example had a large specific volume, it turned out that it was flexible and supple, and was excellent in the texture.

  The composite nonwoven fabric of this invention can be used also as a nonwoven fabric which comprises disposable wearing articles, such as disposable clothing other than the absorbent article like the said embodiment.

It is a schematic diagram which shows one Embodiment of the manufacturing process by the manufacturing method of the composite nonwoven fabric of this invention. It is a schematic diagram which shows one form of the composite nonwoven fabric manufactured by the manufacturing method of the composite nonwoven fabric of this invention, (a) is a perspective view, (b) is sectional drawing. It is a schematic diagram which shows other embodiment of the manufacturing process by the manufacturing method of the composite nonwoven fabric of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite nonwoven fabric 10 Nonwoven fabric 11 1st nonwoven fabric 12 2nd nonwoven fabric

Claims (4)

  A non-woven fabric produced using a fiber web opened by a card machine as a raw material is fed out from the raw material wound in the form of a roll, heated to perform a bulk recovery process, and then the first non-woven fabric is produced. A non-woven fabric and a second non-woven fabric that is different from the first non-woven fabric are embossed and embossed, and these non-woven fabrics are partially joined and integrated to form a composite nonwoven fabric.   The manufacturing method of the composite nonwoven fabric of Claim 1 which heats in the said bulk recovery process by spraying a hot air on the said nonwoven fabric by an air through system, or heating with a heating source.   The manufacturing method of the composite nonwoven fabric of Claim 1 or 2 which manufactures the said nonwoven fabric before performing the said bulk recovery process by an air through system.   The manufacturing method of the composite nonwoven fabric in any one of Claims 1-3 which manufactures a 2nd nonwoven fabric by an air through system using the fiber web opened with the card machine.

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