JP6708107B2 - Shaped non-woven fabric - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shaped nonwoven fabric which is bulky and has pores, and a product using the shaped nonwoven fabric.

In recent years, nonwoven fabrics used for sanitary materials such as disposable diapers and sanitary napkins have been required to be more comfortable and have been improved. In particular, special non-woven fabrics have come to be used for surface materials in order to reduce skin irritation and stuffiness caused by urine and menstrual blood. For example, in order to reduce the contact area with the skin, shaped non-woven fabrics and non-woven fabrics having perforations to increase the absorption rate are mentioned.

As a conventional non-woven fabric having an opening, a non-woven fabric having an opening formed by piercing with a heated pin while sandwiching the non-woven fabric with a pin roll and a ridge roll is known (for example, Patent Document 1). reference). However, this method has a problem that the nonwoven fabric is crushed by the pin rolls, so that the bulkiness of the nonwoven fabric is reduced and the texture is deteriorated. In addition, since the non-woven fabric is compacted except for the openings, it is difficult for liquid to pass therethrough, and the bulk becomes low, and there is a problem that liquid returns frequently.

In order to solve these problems, a shaped non-woven fabric that has been perforated and shaped by a perforating device that combines a ridge roll and a piercing pin roll has been studied (for example, see Patent Document 2). However, since the shape-imparted part is the shape formed by being compressed by the ridge roll, there is a problem that the liquid is difficult to pass through. In addition, the shape retention is low due to the tension (tensile force) of the non-woven fabric, and when the disposable diaper is processed or a sanitary napkin is processed, the shape-imparted portion is broken, which lowers the shape retention. Had.

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

In view of the above, it is an object of the present invention to provide a shaped nonwoven fabric having an open hole, which is excellent in texture, has good liquid permeability, is bulky, and has improved liquid return.

The present inventor has conducted extensive studies in order to solve the above problems. As a result, a relatively low specific volume portion and a high specific volume portion are present linearly on the non-woven fabric surface, and the low specific volume portion is a shaped non-woven fabric in which openings are present. They have found that they can solve the problems and have completed the present invention.

The present invention has the following configurations.
[1] A shaped nonwoven fabric in which a relatively low specific volume portion and a high specific volume portion are present linearly in parallel on the nonwoven fabric surface. A shaped non-woven fabric having pits that have alternating pores and a high specific volume with ridges that have not been heat-compressed.
[2] The shaped nonwoven fabric according to [1], which has a region with a low specific volume at the center of the nonwoven fabric cross section in the nonwoven fabric cross section of the relatively high specific volume portion of the nonwoven fabric surface.
[3] The shaped nonwoven fabric according to [1], which has a region with a high specific volume at the center of the nonwoven fabric cross section in the nonwoven fabric cross section of the relatively high specific volume portion of the nonwoven fabric surface.
[4] The shaped non-woven fabric specific volume ratio according to any one of [1] to [3] above, which has a specific volume ratio defined by the following formula of 5% or more and less than 50% = a portion having a low specific volume Specific volume/specific volume in high specific volume part×100

The shaped nonwoven fabric of the present invention is bulky and has excellent texture. Furthermore, the shaped nonwoven fabric of the present invention has ridges that are not heat-compressed in the portion having a relatively high specific volume, and the heat-compressed portion and the open holes in the portion having a relatively low specific volume. The liquid passing time is short (absorption rate is fast) because it has parts and parts alternately, and the liquid passing property is good and bulky, so the liquid return property is reduced and it is good. It has various characteristics.

It is a photograph of a cross-sectional view of a nonwoven fabric showing an embodiment of the shaped nonwoven fabric of the present invention. It is a photograph of a cross-sectional view of a nonwoven fabric showing an embodiment of the shaped nonwoven fabric of the present invention. It is the photograph seen from the upper surface of the shaped nonwoven fabric of the present invention. It is the schematic diagram seen from the front of the pair of thermal compression shaping rolls used in the present invention. It is a schematic diagram which shows having the area|region (5) with a low specific volume in the center of a nonwoven fabric cross section in the cross section of the nonwoven fabric in the part with a relatively high specific volume of the shaped nonwoven fabric of this invention. 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 a nonwoven fabric in the part with a relatively high specific volume of the shaped nonwoven fabric of this invention.

The shaped nonwoven fabric of the present invention is a shaped nonwoven fabric in which a relatively low specific volume portion and a high specific volume portion are present linearly in parallel on the nonwoven fabric surface, and the low specific volume portion is heat-compressed. The ridges that have a large specific volume have ridges that have not been heat-compressed.
In order to obtain the nonwoven fabric having such a structure, for example, the nonwoven fabric made of the heat-fusible composite fiber may be processed by a thermocompression type pin roller.

The shaped nonwoven fabric of the present invention preferably has a specific volume ratio defined by the following formula of 5% or more and less than 50%.
Specific volume ratio = specific volume in low specific volume portion/specific volume in high specific volume portion x 100 (%)
When the specific volume ratio is 5% or more and less than 50%, even non-woven fabrics having the same thickness have excellent absorbency. 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 non-woven fabric used in the present invention, a non-woven fabric made of a heat-fusible conjugate fiber obtained by thermally adhering a web obtained by the card method with a circulating hot air dryer can be preferably used.
As the heat-fusible composite fiber, polyethylene (PE) such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), crystalline polypropylene, and propylene are main components. Of polypropylene (PP) such as copolymer (Co-PP) of propylene and ethylene or α-olefin, polyethylene terephthalate, polybutylene terephthalate, polyester (PET) such as polyester copolymer (Co-PET) Fiber can be used. Specific combinations include, for example, PP/PE, PP/Co-PP, PET/PE, PET/LLDPE, and PET/Co-PET. Examples of the form of the composite fiber include a sheath-core type, a side-by-side type, and an eccentric sheath-core type.

The fineness of the heat-fusible composite fiber used in the present invention is preferably 0.8 dtex to 20 dtex, and more preferably 1.0 dtex to 10 dtex. In particular, by making the heat-fusible conjugate fiber constituting the non-woven fabric used for the surface layer (the side that comes into contact with the skin) have a finer fineness, the non-woven fabric has good flexibility and texture, and further, smoothness is improved. The friction with and the effect of reducing the rash are enhanced. However, a nonwoven fabric composed of heat-fusible conjugate fibers having a fineness has a problem that the liquid does not easily pass because the number of fiber constituents increases. Therefore, in the present invention, the non-woven fabric is perforated at regular intervals to maintain liquid permeability, but from the viewpoint of the balance between liquid permeability and texture and productivity in processing, use of fiber fine products within this range 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} . Within the above range, the bulk or absorption performance of the nonwoven fabric becomes good. 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 protrusion or a ridge) existing linearly, that is, the width of the protrusion in the CD direction is not particularly limited, but is preferably 2 mm or more and 10 mm or less, and 3 mm or more, It is more preferably 6 mm or less. If it is 2 mm or more, sufficient ridges can be formed, and the effects of the present invention can be sufficiently obtained. If it is 10 mm or less, the contact area with the skin does not become too large, so that the effect of the present invention can be sufficiently obtained.

The width of a portion having a relatively low specific volume (also referred to as a recess) existing linearly, 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 2 mm or more and 6 mm or less. More preferable. If the recess is 1 mm or more, the recess can be formed, and if it is 10 mm or less, the number of the consolidated parts does not increase too much and liquid absorption is not hindered, which is preferable.

As long as the width of the convex portion and the concave portion is within the above range, the width of the unevenness may not be constant. Further, the shapes of the boundary lines of the irregularities such as a wave pattern and a jagged pattern are not particularly limited as long as they are arranged on a substantially straight line.

The diameter of the opening of the opening of the recess is preferably 0.5 mm to 5 mm when the hole is substantially circular, for example. Moreover, it is preferable that the distance between the openings is 1 mm or more and 10 mm or less. Within the above range, the balance between the liquid passage time and the liquid return amount becomes good. The smaller the diameter of the openings and the larger the distance between the openings, the smaller the amount of liquid return, but the longer the passage time, and conversely, the larger the diameter of the openings, the larger the distance between the openings. The narrower the flow, the shorter the liquid passing time, but the more the liquid returns. If the interval is too wide, the liquid passing time tends to be long.

The shaped non-woven fabric of the present invention is made of a non-woven fabric obtained by a circulating hot air dryer of the card method as a raw material, and a convex portion (pin roll) that enables compression punching and a portion that is recessed to leave the thickness of the non-woven fabric Drilling and shaping with a shaping roll for thermal compression consisting of an upper heat roll and a lower heat roll that has holes in the portions that receive pin rolls alternately in the width direction (see Fig. 4. Vertical temperature of rolls 115°C) It can be manufactured by performing.

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

The shaped non-woven fabric of the present invention may be formed by further laminating non-woven fabrics composed of upper and lower two layers of the heat-fusible composite fiber and providing holes communicating in the length direction thereof. The manufacturing method is not particularly limited as long as such communicating holes can be obtained. For example, by forming a space (hollow part) formed by stacking an upper layer and a 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 has high shape retention. .. With such a configuration, the shaped nonwoven fabric of the present invention has the effects of speeding up the drying of the liquid and improving the dryness of the nonwoven fabric. The shaped nonwoven fabric of the present invention may be formed by stacking two nonwoven fabrics having a specific volume difference in one nonwoven fabric. In this case, in the laminated cross section of the shaped nonwoven fabric, a structure having a region with a low specific volume can be formed in the center thereof, or a structure having a region with a high specific volume can be formed in the center thereof.

The surface of the non-woven fabric obtained by the circulating hot air dryer of the card method consists of the net surface on the side of the conveyor and the net surface opposite to it (hereinafter sometimes referred to as fuzzy surface). Since it is pressed onto the conveyor, the specific volume is relatively low, and the fuzzy surface has a relatively high specific volume.
When the shaping process is performed so that the upper and lower two-layer non-woven fabric has a communicating hole, the shaped non-woven fabric obtained has a non-woven fabric cross-section of a part having a high specific volume of the surface, and the above-mentioned net surface. Four types of patterns can be selected depending on which of the fuzzy surfaces is to be turned up. Of the patterns, FIGS. 5 and 6 show a structure of a good combination particularly for use as a sanitary material.
Regarding 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 comes into contact with the skin has a problem of rash due to fluff caused by raising of the nonwoven fabric. Therefore, the net surface is preferably the upper layer.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.

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

<Method for evaluating bulkiness of non-woven fabric>
As a sample, a non-woven fabric cut into 100 mm×100 mm is used, and the basis weight of the non-woven fabric is measured, and the value is A (g/m ² ).
The thickness of the sample for which the fabric weight is measured is measured at four points using a Digithic tester, and the arithmetic mean value thereof is B (mm).
The specific volume (nonwoven fabric density) is calculated from these values by the following formula. The higher the specific volume, the higher the bulkiness.
Specific volume=B/A×1000 (cm ³ /g)

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

<Evaluation method of absorption performance>
The absorption performance was comprehensively judged from (1) evaluation of initial liquid permeability and repeated liquid permeability, and (2) liquid return property evaluation.
(1) Evaluation of initial liquid permeability and repeated liquid permeability Based on the measurement method of liquid passage time of EDANA ERT 150.3-96, measure the time for liquid to pass through the nonwoven fabric sample (liquid passage time). The liquid permeability was evaluated by. As a specific method, four sheets of absorbent paper (Kim towel (trade name) manufactured by Crecia Co., Ltd.) are placed on an acrylic plate holder and folded in four, and then folded into two, and a 100 mm×100 mm square non-woven fabric is placed thereon. Place the sample. It was set in a holder, 10 ml of physiological saline was poured with a buret, and the passage time was measured. As the physiological saline, an aqueous solution was used in which 9 g of NaCl was completely melted in ion-exchanged water to 1000 g. The second passage time of the same sample was measured by leaving it for 1 minute after the completion of the first measurement, then sandwiching the sample between 8 sheets of absorbent paper and placing a weight of 35 g/cm ² for 1 minute, and After air-drying for 3 minutes, the second passage time was measured. This was repeated 3 times. It is shown that the shorter the initial (first) liquid passage time and the liquid passage time after three times of repetition, the better the liquid permeability.
(2) Evaluation of liquid return property Evaluation was made by a method according to EDANA-ERT 151.1-96. The absorbent paper used was a towel made by Crecia Co., Ltd. (trade name) cut into about 90 mm x 90 mm (adjusted to be 5.00 to 5.05 g), and a saline solution measured with a buret. 17 ml was permeated and absorbed. The liquid return amount was evaluated according to the following criteria. The smaller the amount of liquid returned, the better the nonwoven fabric was judged.
◯: less than 4 g Δ: 4 g or more, less than 4.5 g x: 4.5 g or more

<Flexibility evaluation method>
The flexibility was evaluated by 10 panelists according to the following evaluation criteria.
◯: The number of people who felt flexible was 8 or more.
Δ: The number of people who felt flexible was 5 or more and 7 or less.
X: The number of people who felt to be flexible is 4 or less.
In this evaluation method, a non-woven fabric having a rating of ◯ or Δ was evaluated as having high flexibility.

<Cushioning property evaluation method>
The cushioning property was evaluated by 10 panelists according to the following evaluation criteria.
◯: The number of people who felt repulsive was 8 or more.
Δ: The number of people who felt repulsive is 5 or more and 7 or less.
X: The number of people who felt that they had resilience was 4 or less.
The non-woven fabric that was evaluated as ◯ or Δ in this evaluation method was evaluated as having high cushioning property.

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 Sanbo Co., Ltd.

<Sample 1>
A non-woven fabric having a basis weight 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 of PE, and a core component of PET, and a shaping roller (upper and lower temperature of the roller: 120° C.) The hole was shaped by drilling.
The obtained sample 1 had a thickness of 0.73 mm, a specific volume of 29.2 (cm ³ /g), and a high specific volume portion had ridges that were not thermally compressed. ..

<Sample 2>
A nonwoven fabric having a basis weight 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 of PE, and a core component of PET is used as the upper layer, and has a fineness of 2.6 dtex and a sheath-core area. A shaping roller for two layers (upper and lower temperature of roller: 120° C.) using a non-woven fabric having a basis weight of 25 g/m ² composed of a sheath-core type composite fiber having a ratio of 50/50 of PE as a core component and PET as a core component as a lower layer. The hole was shaped by drilling.
The obtained sample 2 had a thickness of 1.5 mm and a specific volume of 30.6 (cm ³ /g), and the high specific volume portion had ridges that were not thermally compressed. ..

<Sample 3>
A non-woven fabric with a basis weight 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 of PE, and a core of PET, and a core component of PET. (Upper and lower temperatures of 115° C.) were used to perform drilling and shaping.
The obtained sample 3 had a thickness of 0.35 mm and a specific volume of 14.0 (cm ³ /g), and the high specific volume portion was formed by a heat roll combining an uneven embossing roll and a pin roll. It had ridges that were heat pressed.

<Sample 4>
A nonwoven fabric having a basis weight 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 of PE, and a core component of PET is used as the upper layer, and has a fineness of 2.6 dtex and a sheath-core area. Using a non-woven fabric having a basis weight of 25 g/m ² composed of a sheath-core composite fiber having a ratio of 50/50 of PE as the core component and PET as the core component as the lower layer, an uneven embossing roll (upper and lower temperature of the roll 80° C.) was used to apply the upper layer. After performing shaping, 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 had a thickness of 0.79 mm and a specific volume of 16.7 (cm ³ /g), and the high specific volume portion had ridges that were heat-compressed by the uneven embossing roll. Was.

Example 1 (Reference Example 1)
Sample 1 is a shaped non-woven fabric having an opening made of a single layer non-woven fabric processed by using a shaping roller (FIG. 1). It can be seen that the specific volume is high and bulky. Also, in the evaluation of the texture by 10 panelists, 8 panelists evaluated that it had flexibility, and 5 panelists evaluated that it had high cushioning property, which was 5 points.
Regarding the absorption performance, the liquid permeability is high due to the perforation effect, and the effect of initial liquid permeability and repeated liquid permeability is high. Further, in the liquid return, the amount of the liquid return is small because the shaped convex portion is bulky. The specific volume ratio was 5.9/29.2×100=20%.

Example 2
Sample 2 is a shaped non-woven fabric having an opening made of a two-layer non-woven fabric processed using a shaping roller (FIG. 2). It can be seen that the specific volume is high and bulky. Also, in the evaluation of the texture by 10 panelists, 8 panelists evaluated that it had flexibility, and 8 panelists evaluated that it had high cushioning property.
Regarding the absorption performance, the liquid permeability is high due to the perforated effect, and the initial liquid permeability and the repeated liquid permeability are high. Further, in the liquid return, the amount of the liquid return is small because the shaped convex portion is bulky. The specific volume ratio was 4.9/30.6×100=16%.

Comparative Example 1
Sample 3 is a sample shaped by an uneven embossing roll. The sample 3 had a high specific volume, but was easily crushed because the convex portions were hollow. Further, the shape-maintaining property is poor with respect to tensile stress. According to the texture evaluation by 10 panelists, 4 panelists felt that they were soft and 4 panelists felt that they had high cushioning property.
The absorption performance has the effect of the initial liquid permeability and the repeated liquid permeability due to the perforation effect, but since the whole nonwoven fabric is compacted, 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 non-woven fabric in which the upper layer concavo-convex embossed non-woven fabric is fixed by the lower layer, but although the specific volume is high and the lower layer has a shape-maintaining property, the convex portion is hollow, so it is crushed It was easy. According to the texture evaluation by 10 panelists, 5 panelists felt that they were soft and 5 panelists felt that they had high cushioning property.
Regarding the absorbent performance, the initial liquid permeability, especially 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, it is possible to use fibers having a finer fineness without deteriorating initial liquid permeability and repeated liquid permeability. By using fine fibers and leaving the thickness of the non-woven fabric, it is possible to obtain a shaped non-woven fabric having softness and high cushioning property.
The shaped nonwoven fabric obtained in the present invention can be suitably used as a surface material for a sanitary material.

1 Shaped roll for thermal compression 2 Upper heat roll 3 Lower heat roll 4 High specific volume area 5 Low specific volume area 6 High specific volume area 7 High specific volume area

Claims (4)

A shaped non-woven fabric made by stacking two layers of non-woven fabric, where the low specific volume part and the high specific volume part are linearly parallel to each other on the surface of the non-woven fabric. Has a hollow portion formed therein, the low specific volume portion has heat-compressed portions and open hole portions alternately, and the high specific volume portion has a shape having ridges that have not been heat compressed. Non-woven fabric. The shaped nonwoven fabric according to claim 1, which has a region having a low specific volume at the center of the nonwoven fabric cross section in the nonwoven fabric cross section of the relatively high specific volume portion of the nonwoven fabric surface. The shaped non-woven fabric according to claim 1, which has a region with a high specific volume at the center of the cross section of the non-woven fabric in the non-woven fabric cross section of the part of the non-woven fabric surface having a relatively high specific volume. The shaped nonwoven fabric according to any one of claims 1 to 3, wherein the specific volume ratio defined by the following formula is 5% or more and less than 50%.
Specific volume ratio = specific volume in low specific volume portion/specific volume in high specific volume portion x 100 (%)

Images