JP2018090932A - Shaped nonwoven fabric - Google Patents

Abstract

An object of the present invention is to provide a shaped non-woven fabric having an aperture having excellent texture, good liquid permeability, bulky and improved liquid return. A shaped nonwoven fabric in which a portion having a relatively low specific volume and a portion having a high specific volume exist in a straight line parallel to each other on the surface of the nonwoven fabric, and the portion having a low specific volume is a portion subjected to thermal compression. The part which has an open-hole part alternately and a part with a high specific volume is based on the shaping nonwoven fabric which has the wrinkle which is not heat-compressed. [Selection] Figure 1

Description

  The present invention relates to a shaped nonwoven fabric that is bulky and has openings, and a product using the shaped nonwoven fabric.

  In recent years, non-woven fabrics used for sanitary materials such as disposable diapers and sanitary napkins are required to be more comfortable and are being improved. In particular, special non-woven fabrics have been used for the surface material in order to reduce skin irritation and stuffiness due to urine and menstrual blood. For example, in order to reduce the contact area with the skin, a non-woven fabric that has been shaped, or a non-woven fabric having pores to increase the absorption rate can be used.

  As a conventional nonwoven fabric having an aperture, a nonwoven fabric in which an aperture is formed by pinching with a heated pin while sandwiching the nonwoven fabric between a pin roll and a protruding roll is known (for example, Patent Document 1). reference). However, in this method, since the nonwoven fabric is crushed by the pin rolls, there is a problem in that the nonwoven fabric is reduced in volume and the texture is lowered. Moreover, since the non-woven fabric is consolidated except for the openings, there is a problem that the liquid is difficult to pass through, the bulk is lowered, and the liquid returns frequently.

  In order to solve these problems, a shaped nonwoven fabric that has been subjected to opening and shaping by an opening device that combines a protruding roll and a perforated pin roll has been studied (for example, see Patent Document 2). However, since the shaping portion is a shaping formed by being compressed by the ridge roll, there is a problem that the liquid hardly passes. In addition, there is a problem that shaping maintenance is low due to the pulling (tension) of the nonwoven fabric, and the shaping part is broken when processing disposable diapers or sanitary napkins, and the shaping maintenance is reduced. Had.

JP-A-6-330443 JP 2009-215667 A

  In view of the above, an object of the present invention is to provide a shaped non-woven fabric having pores that is excellent in texture, has good liquid permeability, is bulky, and has improved liquid return.

  The present inventor has intensively studied to solve the above problems. As a result, a portion having a relatively low specific volume and a portion having a high specific volume are linearly present on the surface of the nonwoven fabric, and a portion having a low specific volume is formed into a shaped non-woven fabric having pores. The present inventors have found that the problem can be solved and have completed the present invention.

The present invention has the following configuration.
[1] A shaped nonwoven fabric in which a portion having a relatively low specific volume and a portion having a high specific volume are present in a straight line parallel to the nonwoven fabric surface. A shaped non-woven fabric having alternating hole portions and a portion having a high specific volume having wrinkles that are not thermally compressed.
[2] The shaped nonwoven fabric according to [1], which has a region having a low specific volume at the center of the nonwoven fabric cross section in a nonwoven fabric cross section at a relatively high specific volume on the nonwoven fabric surface.
[3] The shaped nonwoven fabric according to [1], which has a region having a high specific volume at the center of the nonwoven fabric cross section in a section of the nonwoven fabric having a relatively high specific volume on the surface of the nonwoven fabric.
[4] The specific volume ratio defined by the following formula is 5% or more and less than 50%, the shaped nonwoven fabric specific volume ratio according to any one of the above [1] to [3] = a portion having a low specific volume Specific volume / specific volume at a high specific volume portion × 100

  The shaped nonwoven fabric of the present invention is bulky and excellent in texture. Furthermore, in the shaped nonwoven fabric of the present invention, the portion having a relatively high specific volume has wrinkles that are not thermally compressed, and the portion having a relatively low specific volume is divided into the portion compressed by the heat compressed portion and the aperture. Since it has alternating portions, the liquid passage time is short (absorption speed is fast), the liquid permeability is good, and the bulkiness is high, so the liquid return property is reduced and good. It has special characteristics.

It is a photograph of the cross-sectional view of the nonwoven fabric which shows one Embodiment of the shaped nonwoven fabric of this invention. It is a photograph of the cross-sectional view of the nonwoven fabric which shows one Embodiment of the shaped nonwoven fabric of this invention. It is the photograph seen from the upper surface of the shaping nonwoven fabric of this invention. It is the schematic diagram seen from the front of a pair of shaping roll for heat compression used for this invention. In the cross section of the nonwoven fabric in the relatively high specific volume part of the shaped nonwoven fabric of this invention, it is a schematic diagram which shows having a low specific volume area | region (5) in the center of a nonwoven fabric cross section. It is a schematic diagram which shows having the area | region (6) with a high specific volume in the center of a nonwoven fabric cross section in the cross section of the nonwoven fabric in the relatively high specific volume part of the shaped nonwoven fabric of this invention.

The shaped nonwoven fabric of the present invention is a shaped nonwoven fabric in which a portion having a relatively low specific volume and a portion having a high specific volume are present in a straight line parallel to the nonwoven fabric surface. The portions having the specific volume and the aperture portions are alternately provided, and the portion having a high specific volume has a wrinkle that is not thermally compressed.
In order to obtain a nonwoven fabric having such a structure, for example, a nonwoven fabric made of a heat-fusible conjugate fiber may be processed with a thermocompression-type pin roller.

In the shaped nonwoven fabric of the present invention, the specific volume ratio defined by the following formula is preferably 5% or more and less than 50%.
Specific volume ratio = specific volume in a low specific volume portion / specific volume in a high specific volume portion × 100 (%)
If the specific volume ratio is 5% or more and less than 50%, the non-woven fabric having the same thickness is excellent in absorbability. The specific volume ratio is more preferably 5% or more and 45% or less, and further preferably 10% or more and 40% or less in terms of bulkiness.

As the nonwoven fabric used in the present invention, a nonwoven fabric made of a heat-fusible conjugate fiber obtained by heat-bonding a web obtained by the card method with a circulating hot air dryer can be preferably used.
The heat-fusible conjugate fiber includes polyethylene (PE) such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), crystalline polypropylene, and propylene as main components. Composites combining polypropylene (PP) such as a copolymer of propylene and ethylene or α-olefin (Co-PP) (polyethylene terephthalate, polybutylene terephthalate, polyester copolymer (Co-PET), etc.) Fiber can be used. Specific examples include PP / PE, PP / Co-PP, PET / PE, PET / LLDPE, and PET / Co-PET. Moreover, as a form of composite fiber, a sheath core type, a parallel type, an eccentric sheath core type, etc. are mentioned.

  The fineness of the heat-fusible conjugate fiber used in the present invention is preferably 0.8 dtex to 20 dtex, more preferably 1.0 dtex to 10 dtex. In particular, the heat-fusible conjugate fiber that forms the nonwoven fabric used for the surface layer (the side that touches the skin) has a finer fineness, so that the flexibility and texture of the nonwoven fabric are improved and the smoothness is improved. The effect of reducing rash is increased. However, a nonwoven fabric composed of heat-fusible conjugate fibers with a fine fineness increases the number of fiber components, which causes a problem that liquid is difficult to pass through. Therefore, in the present invention, the nonwoven fabric is perforated at regular intervals to maintain liquid permeability, but the use of fiber fine products within this range from the balance of liquid permeability and texture and processing productivity. Is preferred.

Woven cloth, when the nonwoven fabric is a single ^layer, preferably ^{10g / m 2 ~100g / m 2} , more preferably ^{15g / m 2 ~70g / m 2} . If it is in the said range, the volume or absorption performance of a nonwoven fabric will become favorable. Also, if the nonwoven fabric is a multilayer, the total basis weight of the multilayer is ^{preferably 10g / m 2 ~100g / m 2} , more preferably ^{15g / m 2 ~70g / m 2} .

  The width of a portion having a relatively high specific volume (also referred to as a convex portion or a ridge) that exists in a straight line, that is, the width of the convex portion in the CD direction is not particularly limited, but is preferably 2 mm or more and 10 mm or less, preferably 3 mm or more, More preferably, it is 6 mm or less. If it is 2 mm or more, a sufficient wrinkle can be formed and the effect by this invention is fully acquired. Moreover, since the contact area with skin will not increase too much if it is 10 mm or less, the effect of this invention is fully acquired.

  The width of the portion having a relatively low specific volume (also referred to as a recess) that exists in a straight line, that is, the width of the recess in the CD direction is not particularly limited, but is preferably 1 mm or more and 10 mm or less, and preferably 2 mm or more and 6 mm or less. Further preferred. If the concave portion is 1 mm or more, the concave portion can be formed, and if it is 10 mm or less, the compacted portion does not increase excessively and liquid absorption is not hindered.

  As long as the widths of the convex portions and the concave portions are within the above range, the width of the concave and convex portions may not be constant. Moreover, as long as it arrange | positions on a substantially straight line, the shape of an uneven | corrugated boundary line, such as a wave pattern and a jagged pattern, is not specifically limited.

  For example, when the hole is substantially circular, the diameter of the opening portion of the recess is preferably 0.5 mm to 5 mm. Moreover, it is preferable that the space | interval of an aperture | open hole is spaced apart by the interval of 1 mm or more and 10 mm or less. By being within the above range, the balance between the liquid passing time and the liquid return amount is improved. As the diameter of the opening is reduced and the distance between the openings is increased, the liquid return amount decreases, but the liquid passing time becomes longer, and conversely, the diameter of the opening is increased. When becomes narrower, the liquid passing time becomes shorter, but the liquid return amount increases. Further, when the interval is too wide, the liquid passing time tends to be long.

  The shaped non-woven fabric of the present invention is made from a non-woven fabric obtained by a card-type circulating hot air dryer, and a convex portion (pin roll) that enables compression drilling and a concave portion that allows the thickness of the non-woven fabric to remain Drilling and shaping with a heat compression shaping roll (see Fig. 4; roll up and down temperature of 115 ° C) consisting of an upper heat roll and a lower heat roll with holes in the part that receives the pin roll alternately in the width direction Can be manufactured.

  The surface to be used for the shaped nonwoven fabric of the present invention is not particularly limited, but when used as a surface material for sanitary materials such as disposable diapers and sanitary napkins, the surface that touches the skin is a problem of rash due to fluff caused by raising of the nonwoven fabric. The net surface is preferably the upper layer.

  The shaped nonwoven fabric of the present invention may be further shaped by laminating nonwoven fabrics composed of two layers of upper and lower heat-fusible conjugate fibers and providing holes communicating in the length direction. If such a communicating hole can be obtained, the manufacturing method is not particularly limited. For example, by forming a space (hollow part) formed by lamination of the upper layer and the lower layer or a density difference (specific volume difference), the cushioning property of the nonwoven fabric is increased, and the nonwoven fabric is bulky and highly shaped and maintainable. . By setting it as such a structure, the shaped nonwoven fabric of this invention has the effect of speeding up drying of a liquid and improving the dryness of a nonwoven fabric. The shaped nonwoven fabric of the present invention may be formed by laminating two nonwoven fabrics having a specific volume difference in one nonwoven fabric. In this case, the layered cross section of the shaped nonwoven fabric can have a structure having a low specific volume region at the center thereof, and can also have a structure having a high specific volume region at the center thereof.

The nonwoven fabric surface obtained with the card-type circulating hot air dryer consists of a net surface on the conveyor side and a net surface on the opposite side (hereinafter sometimes referred to as fuzzy surface). Since it is pressed against the conveyor, the specific volume is relatively low, and the specific volume of the fuzzy surface is relatively high.
When the shaping process is performed so as to have continuous holes made of upper and lower two layers of nonwoven fabric, the obtained shaped nonwoven fabric has the above-described net surface in the nonwoven fabric cross section of the portion having a high specific volume on the surface. Four types of patterns can be selected depending on which of the fuzzy surfaces is on the top. Among the patterns, FIG. 5 and FIG. 6 show a good combination structure particularly for hygiene materials.
For the shaped nonwoven fabric of the present invention, the surface to be used is not particularly limited, but when used as a surface material for sanitary materials such as disposable diapers and sanitary napkins, the surface that touches the skin is a problem of rash caused by fluff caused by raising of the nonwoven fabric Therefore, the net surface is preferably the upper layer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the scope of the present invention is not limited to these.

  The performance of the shaped nonwoven fabric of the present invention was evaluated by the following method.

<Method for evaluating bulkiness of nonwoven fabric>
As a sample, using a non-woven fabric was cut into 100 mm × 100 mm, measured basis weight of the nonwoven fabric, and its value as A (g / ^{m 2).}
The thickness of the sample on which the basis weight is measured is measured at four places using a digital nesting tester, and the arithmetic average value is defined as B (mm).
The specific volume (nonwoven fabric density) is calculated from these values by the following formula. It shows that it is bulky, so that a specific volume is high.
Specific volume = B / A × 1000 (cm ³ / g)

<Specific volume ratio>
The specific volume ratio is calculated from the following formula.
Specific volume ratio = specific volume in a low specific volume portion / specific volume in a high specific volume portion × 100

<Evaluation method of absorption performance>
Absorption performance was comprehensively judged from (1) evaluation of initial liquid permeability and repeated liquid permeability and (2) liquid return evaluation.
(1) Evaluation of initial liquid permeability and repeated liquid permeability Based on the liquid passage time measurement method of EDANA ERT 150.3-96, measure the time (liquid passage time) for the liquid to pass through the nonwoven fabric sample. The liquid permeability was evaluated. As a specific method, an absorbent paper (Crecia Kimtowel Co., Ltd. (product name)) is placed on an acrylic plate holder and placed in a four-fold and two-fold shape, and a 100 mm × 100 mm square non-woven fabric is placed thereon. Place a sample. It set to the holder, 10 ml of physiological saline was poured with the burette, and the liquid passing time was measured. The physiological saline used was an aqueous solution in which 9 g of NaCl was completely melted in ion exchange water to 1000 g. The measurement of the second passage time of the same sample was allowed to stand for 1 minute after the completion of the first measurement, and then the sample was sandwiched between 8 sheets of upper and lower absorbent paper and placed under a load of 35 g / cm ² for 1 minute. After air-drying for 3 minutes, the second flow time was measured. This was repeated three times. The shorter the initial (first) flow time and the 3rd repeated flow time, the better the liquid permeability.
(2) Liquid return evaluation It evaluated by the method according to EDANA-ERT 151.1-96. The absorbent paper used was a crecia Kim Towel (trade name) cut into approximately 90 mm x 90 mm (adjusted to be 5.00 to 5.05 g), and physiological saline weighed with a burette 17 ml was permeated and absorbed. The liquid return amount was evaluated according to the following criteria. The smaller the liquid return amount, the better the nonwoven fabric.
○: Less than 4 g Δ: 4 g or more, less than 4.5 g ×: 4.5 g or more

<Flexibility evaluation method>
Ten panelists evaluated the flexibility according to the following evaluation criteria.
○: The number of people who felt flexible was 8 or more.
(Triangle | delta): The number of people who felt flexible is 5 or more and 7 or less.
X: The number of people who felt flexible was 4 or less.
In this evaluation method, the nonwoven fabric evaluated as “◯” or “Δ” was evaluated as having high flexibility.

<Cushioning evaluation method>
The cushioning properties were evaluated by 10 panelists according to the following evaluation criteria.
○: The number of people who felt resilience was 8 or more.
(Triangle | delta): The number of people who felt there is resilience is 5 or more and 7 or less.
X: The number of persons who felt that there was resilience is 4 or less.
In this evaluation method, the nonwoven fabric that was evaluated as ○ or Δ was evaluated as having high cushioning properties.

In Examples and Comparative Examples of the present invention, the following PE was used as polyethylene, and the following PET was used as polyester.
PE: M6900 (trade name) manufactured by Keiyo Polyethylene Co., Ltd.
PET: CZ5022 (trade name) manufactured by Sanfang Group Co., Ltd.

<Sample 1>
A non-woven fabric having a weight per unit area of 25 g / m ² made of a sheath-core type composite fiber having a fineness of 1.3 dtex, a sheath-core area ratio of 50/50, PE, and a core component of PET, is formed into a shaping roller (up and down temperature of the roller is 120 ° C.) Drilling and shaping was performed.
The obtained sample 1 had a thickness of 0.73 mm, a specific volume of 29.2 (cm ³ / g), and a portion with a high specific volume had wrinkles that were not thermally compressed. .

<Sample 2>
A non-woven fabric having a basis weight of 25 g / m ² made of a sheath-core composite fiber having a fineness of 1.3 dtex, a sheath-core area ratio of 50/50, PE, and a core component of PET is used as the upper layer, and the fineness is 2.6 dtex, sheath-core area Using a non-woven fabric with a basis weight of 25 g / m ² consisting of a sheath-core type composite fiber with a sheath component of PE of 50/50 and a core component of PET as a lower layer, a two-layer shaping roller (up and down temperature of the roller is 120 ° C.) Drilling and shaping was performed.
The obtained sample 2 had a thickness of 1.5 mm, a specific volume of 30.6 (cm ³ / g), and a portion with a high specific volume had wrinkles that were not thermally compressed. .

<Sample 3>
Heat roll (roll) of a nonwoven fabric with a basis weight of 25 g / m ² consisting of a sheath core type composite fiber having a fineness of 1.3 dtex, a sheath core area ratio of 50/50 and PE, and a core component of PET. Drilling and shaping were performed at an upper and lower temperature of 115 ° C.).
The obtained sample 3 has a thickness of 0.35 mm, a specific volume of 14.0 (cm ³ / g), and a portion with a high specific volume is obtained by a heat roll that combines an uneven emboss roll and a pin roll. Had hot-compressed wrinkles.

<Sample 4>
A non-woven fabric having a basis weight of 25 g / m ² made of a sheath-core composite fiber having a fineness of 1.3 dtex, a sheath-core area ratio of 50/50, PE, and a core component of PET is used as the upper layer, and the fineness is 2.6 dtex, sheath-core area Using a non-woven fabric with a weight per unit area of 25 g / m ² consisting of a sheath / core composite fiber with a sheath component of PE of 50/50 and a PET core component of the core component, the upper layer is applied with an uneven embossing roll (up and down temperature of roll 80 ° C.). After forming, in order to fix the shaping of the upper layer, point bonding was performed with the lower layer using an ultrasonic bonding machine.
The obtained sample 4 has a thickness of 0.79 mm, a specific volume of 16.7 (cm ³ / g), and the portion with a high specific volume has wrinkles thermally compressed by an uneven embossing roll. Was.

Example 1
Sample 1 is a shaped nonwoven fabric having apertures made of a single layer nonwoven fabric processed using a shaped roller (FIG. 1). It can be seen that the specific volume is high and bulky. Also, in the texture evaluation by 10 panelists, 8 panelists evaluated as having flexibility, and 5 panelists evaluated as having high cushioning properties.
As for the absorption performance, the liquid permeability is high due to the perforation effect, and the effects of initial liquid permeability and repeated liquid permeability are high. In liquid return, since the shaping convex part is bulky, the amount of liquid return is small. The specific volume ratio was 5.9 / 29.2 × 100 = 20%.

Example 2
Sample 2 is a shaped nonwoven fabric having apertures made of two layers of nonwoven fabric processed using a shaped roller (FIG. 2). It can be seen that the specific volume is high and bulky. Also, in the texture evaluation by 10 panelists, 8 panelists evaluated as having flexibility and 8 panelists evaluated as having high cushioning properties were highly evaluated.
Also in the absorption performance, with respect to the absorption performance, the liquid permeability is high due to the holed effect, and the effects of initial liquid permeability and repeated liquid permeability are high. In liquid return, since the shaping convex part is bulky, the amount of liquid return is small. The specific volume ratio was 4.9 / 30.6 × 100 = 16%.

Comparative Example 1
Sample 3 is a sample formed by an uneven embossing roll. Although this sample 3 had a high specific volume, it was easily crushed because the convex portion was hollow. In addition, shape retention is poor with respect to tensile stress. According to the texture evaluation by 10 panelists, 4 panelists felt flexible and 4 panelists felt that cushioning was high.
Although the absorption performance has the effects of initial liquid permeability and repeated liquid permeability due to the perforation effect, the entire nonwoven fabric is consolidated, so that the liquid return amount is relatively large. The specific volume ratio was 12.6 / 14.0 × 100 = 90%.

Comparative Example 2
Sample 4 is a two-layer nonwoven fabric in which an upper-layer concavo-convex embossed nonwoven fabric is fixed by a lower layer. However, although the specific volume is high and there is a shape-maintaining property due to the effect of the lower layer, the convex portion is hollow and is crushed. It was easy. In the texture evaluation by 10 panelists, 5 panelists felt flexible and 5 panelists felt that cushioning was high.
In the absorptive performance, the initial liquid permeability, particularly the repeated liquid permeability was very low. The specific volume ratio was 14.5 / 16.7 × 100 = 87%.

Since the shaped nonwoven fabric of the present invention has pores, fibers with finer fineness can be used without lowering the initial liquid permeability and repeated liquid permeability. By using fine fibers and leaving the thickness of the nonwoven fabric, a shaped nonwoven fabric that is flexible and highly cushioning can be obtained.
The shaped nonwoven fabric obtained by this invention can be used conveniently for the surface material for sanitary materials.

DESCRIPTION OF SYMBOLS 1 Forming roll for heat compression 2 Upper heat roll 3 Lower heat roll 4 Part with high specific volume 5 Area with low specific volume 6 Area with high specific volume 7 Part with high specific volume

Claims (4)

  A shaped nonwoven fabric in which a portion having a relatively low specific volume and a portion having a high specific volume are present in a straight line parallel to each other on the surface of the nonwoven fabric, and the portion having a low specific volume includes a thermally compressed portion and an aperture portion. The shaped nonwoven fabric having wrinkles that are alternately heat-compressed and the portion having a high specific volume is not thermally compressed.   The shaped nonwoven fabric according to claim 1, wherein in the nonwoven fabric cross section of the relatively high specific volume portion of the nonwoven fabric surface, the shaped nonwoven fabric has a low specific volume region at the center of the nonwoven fabric cross section.   2. The shaped nonwoven fabric according to claim 1, wherein the nonwoven fabric has a region having a high specific volume at the center of the nonwoven fabric cross section in the nonwoven fabric cross section at a relatively high specific volume on the nonwoven fabric surface. The shaped nonwoven fabric according to any one of claims 1 to 3, wherein a specific volume ratio defined by the following formula is 5% or more and less than 50%.
Specific volume ratio = specific volume in a low specific volume portion / specific volume in a high specific volume portion × 100 (%)

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