WO2012137379A1

WO2012137379A1 - Thermoplastic non-woven fabric

Info

Publication number: WO2012137379A1
Application number: PCT/JP2011/075210
Authority: WO
Inventors: 一哉税所; 矢放　正広; 郁雄上野
Original assignee: 旭化成せんい株式会社
Priority date: 2011-04-06
Filing date: 2011-11-01
Publication date: 2012-10-11
Also published as: CN103459694A; CN103459694B; JP2012021259A; MY187420A; JP5731948B2

Abstract

Provided is a non-woven fabric that has favorable workability, superior flexibility, and high width dimensional stability, and that is suitable as a top sheet, back sheet, side gathering section, or the like of an absorbent article used in a sanitary item. The non-woven fabric comprises a thermoplastic fiber and is characterized by the fiber orientation in the non-woven fabric being 1.05-2.0 inclusive by the MOR value of the degree of molecular orientation, and the stress when extended 3% of the non-woven fabric being 2-10 N/5cm inclusive.

Description

Thermoplastic nonwoven fabric

The present invention relates to a nonwoven fabric made of thermoplastic fibers. More specifically, the present invention is suitable for top sheets, back sheets, side gathers and the like of absorbent articles used for sanitary materials, has high width dimensional stability, excellent flexibility, and good workability. The present invention relates to a nonwoven fabric made of thermoplastic fibers.

In recent years, disposable diapers have been remarkably widespread and their production volume has been increasing rapidly. As a disposable diaper in such an environment, it is important to reduce loss in the production line and to stabilize the quality. In the diaper production line, if the width of the nonwoven fabric is changed, it will cause wrinkles and meandering. In the bonding process with the film, the film will be misaligned and the hot melt agent coating process will be applied. Various problems such as insufficient width and adhesion of hot melt agent to each roll during the process occur. In particular, there is a strong demand for higher speeds as production volumes increase, and facilities have been devised. However, the materials used are not only strong enough to withstand high-speed lines, but also frequently used at low to high speed shifts. A material with little dimensional change that can withstand the change is required.

As a means of suppressing the dimensional change in the width of the nonwoven fabric, it is possible to suppress the dimensional change by increasing the degree of adhesion of the nonwoven fabric fibers by increasing the thermal bonding temperature, increasing the bonding pressure, increasing the embossed area ratio, etc. However, regardless of which method is used, the texture of the nonwoven fabric becomes harder by increasing the degree of adhesion. That is, the conventional means for suppressing the dimensional change in the width of the nonwoven fabric is inferior in flexibility for use as a sanitary material, and it is very difficult to achieve both the flexibility of the nonwoven fabric and the dimensional change in the width.

The problems to be solved by the present invention are suitable for top sheets, back sheets, side gathers and the like of absorbent articles used for sanitary materials, and have high dimensional stability, excellent flexibility, and workability. It is to provide a non-woven fabric made of good thermoplastic fibers.

As a result of intensive studies and repeated experiments to solve the above-mentioned problems, the present inventors have determined that the MOR value of the molecular orientation, which is an index of the degree of fiber orientation of a nonwoven fabric made of thermoplastic fibers, and the stress at low elongation of the nonwoven fabric ( 3% elongation stress) is in a specific range, and the arrangement of the fibers constituting the nonwoven fabric is the flow direction of the production line, so the dimensional change in width due to the tension applied during winding is small, and the nonwoven fabric production process and sanitary material processing process As a result, the present invention has been completed.

Normally, the tension applied to a sheet in a sanitary material production line is generally 1 to 6 kg with respect to the entire width of the diaper. The higher the speed, the higher the tension, but the average is estimated to be about 2 kg / 30 cm. Is done. Therefore, no matter how strong the breaking strength is, the tension applied on the line is easy to deform, and it is highly speed dependent. It can be said that it is excellent in stability.

The inventors of the present invention produce a nonwoven fabric at a collection distance (hereinafter referred to as a vertical pattern length) in the flow direction of the production line when fibers are deposited on the moving collection surface in the nonwoven fabric production process. Therefore, by controlling the MOR value of the degree of molecular orientation representing the fiber orientation to a specific range and making the fibers constituting the nonwoven fabric in the flow direction of the production line, the dimensional change of the width due to the tension during winding is reduced. I found.

Furthermore, for the purpose of improving the process stability in the nonwoven fabric production process and sanitary material processing process, as a result of earnestly examining the relationship between the behavior of the nonwoven fabric under stress, such as process tension, and the meandering and wrinkling in the process, the nonwoven fabric It has been found that running stability is improved by controlling the stress at 3% elongation, which is the stress at low elongation of.

In the non-woven fabric production process and processing process, the process tension and roll peripheral speed applied to the non-woven fabric fluctuate due to travel using multi-stage rolls and high-speed travel of the non-woven fabric. In order to alleviate and absorb the fluctuation and prevent the meandering and wrinkling of the nonwoven fabric, it is desirable that the stress at the time of low elongation of the nonwoven fabric is low. If the nonwoven fabric has a large stress value at 3% elongation, the nonwoven fabric is less likely to follow the fluctuations in the peripheral speed, and is likely to cause meandering and wrinkling. On the other hand, if the value of the stress at 3% elongation is too small, the nonwoven fabric is stretched by the process tension, and the running is not stable. Furthermore, the softness | flexibility suitable for a sanitary material can be hold | maintained by controlling the value of 3% elongation stress small.

That is, in the sanitary material production line, by controlling the fiber orientation of the nonwoven fabric, the dimensional change of the width in the process is suppressed, and by controlling the stress at 3% elongation of the nonwoven fabric, the process tension and speed are controlled. Achieved stable running improvement by following and absorbing fluctuations.

That is, the present invention is as follows.
[1] A nonwoven fabric made of thermoplastic fibers, wherein the fiber orientation in the nonwoven fabric is 1.05 or more and 2.0 or less in terms of MOR of molecular orientation, and the stress at 3% elongation of the nonwoven fabric is 2N / 5cm or more and 10N / 5cm or less, The nonwoven fabric characterized by the above-mentioned.

[2] The nonwoven fabric according to [1], wherein the nonwoven fabric has a vertical / horizontal strength ratio of 1.5 or more and 10 or less.

[3] The nonwoven fabric according to [1] or [2], wherein the width dimension change of the nonwoven fabric is 0% or more and 10% or less.

[4] The nonwoven fabric according to any one of [1] to [3], wherein the thermoplastic fiber is a polyolefin-based fiber.

[5] The nonwoven fabric according to [4], wherein the polyolefin fiber is a polypropylene fiber.

[6] The nonwoven fabric according to any one of [1] to [5], wherein the nonwoven fabric is a long-fiber nonwoven fabric.

[7] The nonwoven fabric according to any one of [1] to [6], wherein the thermoplastic fiber has an average single yarn fineness of 0.5 dtex to 3.5 dtex.

[8] A sanitary material using the nonwoven fabric according to any one of [1] to [7].

[9] The sanitary material according to [8], which is in the form of a disposable diaper, a sanitary napkin, or an incontinence pad.

The nonwoven fabric of the present invention is a nonwoven fabric made of thermoplastic fibers, the fiber orientation is 1.05 or more and 2.0 or less in terms of molecular orientation, and the stress at 3% elongation is 2N / 5cm or more and 10N / 5cm or less. By doing so, the width dimension change becomes very small while maintaining flexibility, and the processability of the sanitary material becomes very good.
In particular, in order to increase the production capacity, it is necessary to increase the production speed of the nonwoven fabric and the production speed of the diaper. As the speed increases, the winding tension generally becomes high. Non-woven fabric production yield is good due to low dimensional change. Also, in the hygiene material production line, deviation from the film in the film bonding process is reduced. Problems such as the hot melt agent adhering to each roll can be reduced.

Hereinafter, the present invention will be described in detail.
Examples of the thermoplastic fiber constituting the nonwoven fabric of the present invention include polyolefin fibers such as polyethylene fiber, polypropylene fiber and copolymer polypropylene, polyesters such as polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber and copolymer polyester. Polyamide fibers such as nylon fiber, nylon-6 fiber, nylon-66 fiber and copolymer nylon, and biodegradable fibers such as polylactic acid, polybutylene succinate and polyethylene succinate are used.

Of these, polyolefin fibers are preferred from the viewpoint of texture. Examples thereof include fibers made of a resin such as polyethylene, polypropylene, and a copolymer of those monomers and other α-olefins. Among them, it is preferable to use polypropylene fiber because it is strong and difficult to break during use, and is excellent in dimensional stability during production of sanitary materials. Polypropylene may be a polymer synthesized by a general Ziegler-Natta catalyst or a polymer synthesized by a single site active catalyst typified by metallocene. Other α-olefins are those having 3 to 10 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexane, 4-methyl-1-pentene, and 1-octene. Can be mentioned. Further, ethylene random copolymer polypropylene may be used, and the ethylene content is preferably less than 2%, preferably less than 1%. These may be used alone or in combination of two or more. It is preferable to use one kind alone. Or the core-sheath fiber which uses a polyolefin-type resin as a surface layer may be sufficient. Moreover, the fiber shape may be not only a normal circular fiber but also a specially shaped fiber such as a crimped fiber and a deformed fiber. From the viewpoint of strength and dimensional stability, it is particularly preferable that the main component is homopolypropylene.
In the case of polypropylene, the lower limit of MFR is 20 g / 10 minutes or more, preferably more than 30 g / 10 minutes, more preferably more than 40 g / 10 minutes, and still more preferably more than 53 g / 10 minutes. The upper limit is 100 g / 10 min or less, preferably 85 g / 10 min or less, more preferably 70 g / 10 min or less, and even more preferably less than 65 g / 10 min. When the MFR is in this range, the resin has good fluidity, the stress at 3% elongation can be lowered, the flexibility as a nonwoven fabric is good, and the nonwoven fabric can be produced stably. MFR is measured according to JIS-K7210 “Testing methods for plastic-thermoplastic melt mass flow rate (MFR) and melt volume flow rate (MVR)”, test temperature 230 ° C., test load 2.16 kg. I went and asked.

In the thermoplastic fiber constituting the nonwoven fabric of the present invention, a nucleating agent, a flame retardant, an inorganic filler, a pigment, a colorant, a heat stabilizer, an antistatic agent, and the like may be blended depending on the purpose.

Examples of the joining means for producing a nonwoven fabric by joining thermoplastic fibers include a partial thermocompression bonding method, a hot air method, a joining with a molten component (hot melt agent) method, and various other methods. Therefore, the partial thermocompression bonding method is preferable.

The area ratio of thermocompression bonding in the partial thermocompression bonding of the nonwoven fabric of the present invention is 3% or more and 40% or less, preferably 4% or more and 25% or less, more preferably 4% or more and 20%, from the viewpoint of strength retention and flexibility. Or less, more preferably 5% or more and 15% or less, and most preferably 7% or less.

In addition, the partial thermocompression treatment of the present invention can be performed by an ultrasonic method or by passing a web between heated embossing rolls, whereby the front and back are integrated, for example, pinpoint shape, elliptical shape, diamond shape In addition, a floating pattern such as a rectangular shape or a slanted ridge shape is scattered all over the nonwoven fabric. From the viewpoint of productivity, it is preferable to use a heated embossing roll.

The average single yarn fineness of the thermoplastic fiber constituting the nonwoven fabric of the present invention is preferably 0.5 dtex or more and 3.5 dtex or less, more preferably 0.7 dtex or more and 3.2 dtex or less, and still more preferably 0.8. 9 dtex or more and 2.8 dtex or less, and most preferably 2.5 dtex or less. From the viewpoint of spinning stability, it is preferably 0.5 dtex or more, and the finer the fineness, the higher the strength and flexibility of the nonwoven fabric because the number of bonding points of the yarn increases. Since it is mainly used for sanitary materials, it is preferably 3.5 dtex or less from the viewpoint of the strength of the nonwoven fabric.

The basis weight of the nonwoven fabric of the present invention is 8 g / m ² or more and 40 g / m ² or less, preferably 10 g / m ² or more and 30 g / m ² or less, more preferably 10 g / m ² or more and 25 g / m ² or less, and still more preferably. is less than 10 g / ^{m 2} or more 23 g / ^{m 2,} and most preferably less than 20 g / ^{m 2.} The thinner the nonwoven fabric, the better the flexibility and the better it can be used as a sanitary material. However, if it is 8 g / m ² or more, it satisfies the strength requirements required for nonwoven fabrics used in sanitary materials. On the other hand, if it is 40 g / m ² or less, the flexibility of the nonwoven fabric used for the sanitary material is satisfied, and the impression of thick appearance is not given.

The MOR value of the degree of molecular orientation, which is an index of fiber orientation of the nonwoven fabric of the present invention, needs to be 1.05 or more and 2.0 or less, preferably 1.1 or more and 2.0 or less, more preferably 1. It is 15 or more and 1.7 or less, More preferably, it is 1.2 or more and 1.7 or less. If the MOR value is 1.05 or more, the fiber orientation becomes the flow direction of the production line, the change in the width dimension is very small, and the sanitary article has good processing suitability. Further, when the MOR value is 2.0 or less, the transverse strength is sufficiently obtained when used as a sanitary material.

The stress at the time of 3% elongation of the nonwoven fabric of the present invention needs to be 2 N / 5 cm or more and 10 N / 5 cm or less, preferably 2 N / 5 cm or more and 8 N / 5 cm or less, more preferably 2.5 N / 5 cm or more and 7.5 N. / 5 cm or less. If the stress at 3% elongation is 10 N / 5 cm or less, the nonwoven fabric used for the sanitary material has good flexibility, and if it is 2 N / 5 cm or more, the nonwoven fabric can be produced stably.

The vertical / horizontal strength ratio of the nonwoven fabric of the present invention is 1.5 or more and 10 or less, preferably 2.0 or more and 10 or less, more preferably 2.5 or more and 8.5 or less, and further preferably 3.0 or more and 8. 5 or less. If the length / width strength ratio is 1.5 or more, the change in width dimension is very small and the processability (or processability) of the sanitary material is good. From the viewpoint of the strength of the nonwoven fabric used for the sanitary material, The horizontal strength ratio is preferably 10 or less. If the length / width strength ratio is increased too much, the winding tension at the time of sanitary material processing may be concentrated at a location where the nonwoven fabric has low stress, and may break.

As the strength of the nonwoven fabric of the present invention, a minimum strength is required from the viewpoint of breaking during sanitary material processing. The vertical breaking strength is preferably 10 N / 5 cm or more and 100 N / 5 cm or less, more preferably 10 N / 5 cm or more and 85 N / 5 cm or less, and further preferably 12 N / 5 cm or more and 70 N / 5 cm or less. The transverse breaking strength is preferably 1.2 N / 5 cm or more and 50 N / 5 cm or less, more preferably 1.5 N / 5 cm or more and 40 N / 5 cm or less, and further preferably 1.8 N / 5 cm or more and 30 N / 5 cm or less. When the breaking strength is within this range, it can be satisfactorily processed without sacrificing at the time of sanitary material processing.

The fiber arrangement of the nonwoven fabric of the present invention is obtained by setting the vertical pattern length, which is the distance in the flow direction of the production line at the landing position of the web when the fibers are deposited on the moving collection surface, to 50 mm or more during web lamination. Preferably, they are 60 mm or more and 400 mm or less, More preferably, they are 75 mm or more and 300 mm or less. If the length of the vertical pattern is 50 mm or more, the change in the width dimension is small and the processing suitability is good. If the length is 400 mm or less, the strength used for the sanitary material can be maintained.

The width change of the present invention is preferably 0% or more and 10% or less, more preferably 0.1% or more and 9% or less, and further preferably 0.5% or more and 8% or less. If the dimensional change of the width is 10% or less, generation of wrinkles is suppressed in the sanitary material production line, and it is preferably 0% or more for stable processing.

A hydrophilizing agent may be applied to the nonwoven fabric of the present invention. As such a hydrophilizing agent, in consideration of safety to the human body, safety in the process, etc., nonionic active agents to which ethylene oxides such as higher alcohols, higher fatty acids, alkylphenols are added, alkyl phosphate salts, alkyls Anionic active agents such as sulfates are preferably used alone or as a mixture.

The application amount of the hydrophilizing agent varies depending on the required performance, but usually it is preferably in the range of 0.1% by weight to 1.0% by weight, more preferably 0.15% by weight to 0%. 0.8 wt% or less, more preferably 0.2 wt% or more and 0.6 wt% or less. When the applied amount is in this range, the hydrophilic performance as a sanitary material top sheet is satisfied, and the processability is also good.

As a method for applying the hydrophilizing agent, an existing method such as a dipping method, a spraying method, a coating (kiss coater, gravure coater) method or the like can be usually employed using a diluted hydrophilizing agent. The mixed hydrophilizing agent is preferably applied after being diluted with a solvent such as water.

When the hydrophilizing agent is diluted with a solvent such as water and applied, a drying process may be required. As a drying method at that time, a known method using convection heat transfer, conduction heat transfer, radiant heat transfer, or the like can be employed, and drying by hot air or infrared rays, drying by heat contact, or the like can be used. .

A softening agent may be applied to the nonwoven fabric of the present invention. Such a softening agent is preferably an ester compound, more preferably an ester compound of a tri- to hexavalent polyol and a monocarboxylic acid.
Examples of the trivalent to hexavalent polyol include trivalent polyols such as glycerin and trimethylolpropane, tetravalent polyols such as pentaerythritol, glucose, sorbitan, diglycerin, and ethylene glycol diglyceryl ether, triglycerin, and trimethylol. Examples include pentavalent polyols such as propanediglyceryl ether, hexavalent polyols such as sorbitol, tetraglycerin, and dipentaerythritol.

Examples of the monocarboxylic acid include alicyclic monocarboxylic acids such as octacarboxylic acid, dodecanoic acid, tetradecanoic acid, octadecanoic acid, docosanoic acid, hexacosanoic acid, octadecenoic acid, docosenoic acid, isooctadecanoic acid, and cyclohexanecarboxylic acid. Aromatic monocarboxylic acids such as carboxylic acid, benzoic acid and methylbenzenecarboxylic acid, hydroxyaliphatic monocarboxylic acids such as hydroxypropionic acid, hydroxyoctadecanoic acid and hydroxyoctadecenoic acid, and sulfur-containing aliphatic monocarboxylic acids such as alkylthiopropionic acid An acid etc. are mentioned.

The ester compound does not need to be a single component, and may be a mixture of two or more kinds or oils and fats derived from natural products. However, saturated aliphatic monocarboxylic acids or aromatic monocarboxylic acids are preferable because ester compounds containing unsaturated fatty acids are easily oxidized and easily deteriorated during spinning. Naturally-derived oils and fats are preferably odorless and stable compared to raw material oils, and therefore, hydrogenated ester compounds are preferably used.

As the ester compound, a monocarboxylic acid having a relatively large molecular weight and high lipophilicity is preferable. Due to the high lipophilicity, it enters the amorphous part of the thermoplastic fiber and inhibits crystallization to increase the amorphous region, so that an effect of reducing the bending flexibility can be obtained.
In order to obtain such an effect, the melting point of the ester compound is preferably 70 ° C. or higher, more preferably 80 ° C. or higher and 150 ° C. or lower. When the melting point of the ester compound is broad and has a range, the melting point means an average melting point. The ester compound may be mixed with other compositions such as an ester compound having a melting point of less than 70 ° C. and other organic compounds.

The content of the ester compound as the softening agent is preferably 0.3% by weight or more and 5.0% by weight or less with respect to the thermoplastic fiber. Even if a small amount of the ester compound is added, the bending flexibility and slipperiness are remarkably improved, and even if the content is increased, the performance improvement corresponding to the content is not seen. Therefore, in consideration of spinnability and smoke generation, it is preferably 5.0% by weight or less, more preferably 0.5% by weight or more and 3.5% by weight or less, and further preferably 0.5% by weight or more and 2.0% by weight or less. % By weight or less.

Although the manufacturing method of the nonwoven fabric of this invention is not specifically limited, Since it is mainly used for a sanitary material, it is preferable that it is a spun bond (S) method from a viewpoint of intensity | strength, and it laminates | stacks with SS, SSS, SSSS. Is preferable because the dispersion is improved. In addition, depending on the purpose, spunbond (S) fibers may be laminated with meltblown (M) fibers, or a structure in which SM, SMS, SMMS, and SMSMS are laminated.
Further, the method for pulling the nonwoven fabric of the present invention is not particularly limited, but in order to obtain a nonwoven fabric having a high MOR value and a small change in width dimension, a method using a high-speed airflow pulling device using an air jet is preferable, and a rectangular type Even better when using a traction device.

The spinning temperature of the thermoplastic fiber constituting the nonwoven fabric of the present invention is from plus 30 ° C. to 100 ° C., preferably plus 40 ° C. to 95 ° C., more preferably plus 45 ° C. to 70 ° C., from the melting point of the thermoplastic resin. More preferably, it is plus 50 degreeC or more and 65 degrees C or less. When two or more types of thermoplastic resins are combined, the melting point of the thermoplastic resin as the main component is used.
For example, when the thermoplastic resin is a polypropylene resin, it is 190 ° C. or higher and 260 ° C. or lower, preferably 200 ° C. or higher and 255 ° C. or lower, more preferably 205 ° C. or higher and 230 ° C. or lower, and further preferably 210 ° C. or higher and 225 ° C. or lower. When the spinning temperature is 260 ° C. or lower, the occurrence of yarn breakage due to less contamination of the spinneret surface due to the resin decomposition product and the lower viscosity of the resin can be suppressed. Moreover, when the spinning temperature is high, the produced nonwoven fabric is affected by the resin decomposition product, so that the strength is lowered, and accordingly, the stress at 3% elongation is also lowered, and it tends to be easily broken during processing. When the spinning temperature is 190 ° C. or higher, the occurrence of yarn breakage due to an increase in the viscosity of the resin can be suppressed, and further, resin leakage due to an increase in the spinneret pressure during spinning can be suppressed.

The nonwoven fabric of the present invention is not particularly limited as long fibers or short fibers depending on the purpose, but is mainly used for sanitary materials. It is preferable that

Since the nonwoven fabric of the present invention has a very small change in width, it can be suitably used for the production of sanitary materials. Examples of the sanitary materials include disposable diapers, sanitary napkins, and incontinence pads, and the tops of their surfaces. It is preferably used for seats, outer backsheets, side gathers around the legs, and the like.
In addition, the use of the nonwoven fabric of the present invention is not limited to the above uses, and examples thereof include masks, warmers, tape base fabrics, waterproof sheet base fabrics, patch medicinal base fabrics, first aid base fabrics, packaging materials, wipe products, and medical gowns. It can also be used for bandages, clothing, skin care sheets and the like.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited only to the following Example.
In addition, the evaluation method of the various characteristics used in the Example and the comparative example is as follows, and the obtained physical property is shown in the following Table 1.

1. Average single yarn fineness (dtex)
Except 10cm at both ends of the manufactured nonwoven fabric, sample a 1cm square test piece by dividing into approximately 5 equal parts in the width direction, measure the diameter of the fiber 20 points at a time with a microscope, and calculate the average single yarn fineness from the average value. did.

2. Weight per unit (g / m ² )
In accordance with JIS-L1906, five test pieces measuring 20 cm in length and 5 cm in width were arbitrarily sampled and the mass was measured, and the average value was converted into the weight per unit area.

3. Vertical / horizontal strength ratio and stress at 3% elongation (N / 5cm)
In accordance with JIS L-1906, except for 10 cm at both ends of the non-woven fabric sample, 5 points of 5 cm wide and 20 cm long samples were cut out so as to be uniform in the width direction. Measured at / min. Samples of 5 points each in the vertical and horizontal directions were measured, and the measured values were averaged to calculate the breaking strength in the vertical direction and the breaking strength in the horizontal direction. The stress at 3% elongation was calculated by averaging the measured values in the vertical and horizontal directions. The vertical / horizontal strength ratio was calculated by the following equation.
Vertical / Horizontal Strength Ratio = Vertical Breaking Strength (N / 5cm) / Horizontal Breaking Strength (N / 5cm)

4). Molecular orientation (MOR value)
Using a molecular orientation meter (manufactured by Oji Scientific Instruments Co., Ltd.) MOA-6004, the polarized microwave is applied to the sample, and the orientation of the principal axis of the molecule is detected by the interaction with the dipole of the fiber molecule. The anisotropy (orientation) was obtained by rotating the sample, and the intensity of transmitted microwaves in the TD and MD directions was obtained. Max / Min value of transmitted microwave intensity = MOR value was determined. This MOR value is a value related to the arrangement ratio of the fibers in the web. When the value is 1, the value is isotropic. When the value is 1 or more, the fibers are arranged in a specific direction. The larger the value, the stronger the arrangement. However, it does not indicate the absolute value of orientation because of measurement by transmission intensity.

5. Dimensional change in width A non-woven fabric sample was cut into a width of 30 cm and a length of 1 m, one end of the sample was fixed with double-sided tape, and the other was attached with a jig (weight: 231.5 g) so that a load could be applied. . A position 80 cm in the length direction from the double-sided tape of the sample is held by a surface chrome-plated free roll (φ80), set so that a load can be applied downward, and a weight of 2 kg is suspended. After 30 seconds, the width at the position of 50 cm in the length direction was measured from the double-sided tape of the sample, and the dimensional change of the width was calculated by the following formula.
Dimensional change (%) = [Width before load set (mm)-2kg after load set (mm)] / Width before load set (mm) x 100

6). Processability with width by winding tension (suitable for processing)
A nonwoven fabric sample having a width of 1 m was wound at a line speed of 200 m / min and a tension of 7 kg / m by a normal winding method known to those skilled in the art, and the degree of occurrence of wrinkles was evaluated according to the following evaluation criteria:
◎: No wrinkle is generated ○: Wrinkles are generated in the line direction ×: Wrinkles are generated or broken in the line direction

[Example 1]
Polypropylene resin with an MFR of 60 g / 10 min (measured at a temperature of 230 ° C. and a load of 2.16 kg according to JIS-K7210) by a spunbond method, nozzle diameter φ0.4 mm, single-hole discharge rate 0.56 g / min · Hole , Extruded at a spinning temperature of 215 ° C., pulled this filament group using a high-speed airflow traction device using an air jet, extruded toward the moving collection surface so as to have a vertical pattern length of 110 mm, and an average single yarn fineness of 1.5 dtex A long fiber web was prepared.

Next, the obtained web was passed between a flat roll and an embossing roll (pattern specification: circular with a diameter of 0.425 mm, staggered arrangement, horizontal pitch 2.1 mm, vertical pitch 1.1 mm, crimping area ratio 6.3%). The fibers were bonded at a temperature of 135 ° C. and a linear pressure of 35 kgf / cm to obtain a long fiber nonwoven fabric having a basis weight of 17 g / m ² .

[Example 2]
A single-hole discharge rate of 0.90 g / min · Hole, a vertical pattern length of 250 mm, and a long fiber nonwoven fabric having an average single yarn fineness of 2.0 dtex and a basis weight of 11 g / m ² were obtained in the same manner as in Example 1.

Example 3
The length of the vertical pattern was 75 mm, and a long fiber nonwoven fabric having an average single yarn fineness of 1.1 dtex and a basis weight of 25 g / m ² was obtained in the same manner as in Example 1.

Example 4
An ethylene / propylene random copolymer having a vertical pattern length of 150 mm, an ethylene component content of 4.3 mol%, and an MFR of 24 g / 10 min (measured at a temperature of 230 ° C. and a load of 2.16 kg according to JIS-K7210). A long fiber nonwoven fabric having an average single yarn fineness of 1.1 dtex and a basis weight of 15 g / m ² was obtained in the same manner as in Example 1 except that the thermocompression bonding temperature was 120 ° C.

Example 5
The length of the vertical pattern is 150 mm, linear low density polyethylene with MFR of 17 g / 10 min (measured at a temperature of 190 ° C. and a load of 2.16 kg according to JIS-K7210) as the sheath component, and MFR of 60 g / 10 min (JIS) According to K7210, measured at a temperature of 230 ° C. and a load of 2.16 kg), a core component and a thermocompression bonding temperature of 132 ° C. were the same as in Example 2 with an average single yarn fineness of 2.0 dtex and a basis weight of 19 g. / M ² long fiber nonwoven fabric was obtained.

Example 6
Polypropylene resin with an MFR of 60 g / 10 min (measured at a temperature of 230 ° C. and a load of 2.16 kg according to JIS-K7210) by a spunbond method, nozzle diameter φ0.48 mm, single hole discharge rate 0.33 g / min · Hole , Extruded at a spinning temperature of 230 ° C., pulled this filament group by a cold air indentation method, extruded toward the moving collection surface so that the length of the warp pattern was 70 mm, and produced a long fiber web having an average single yarn fineness of 1.1 dtex. Prepared.
Next, the fibers were bonded in the same manner as in Example 1 to obtain a long fiber nonwoven fabric having a basis weight of 15 g / m ² .

Example 7
A single-hole discharge amount of 0.66 g / min · Hole, a vertical pattern length of 60 mm, and a long fiber web having an average single yarn fineness of 2.2 dtex were prepared in the same manner as in Example 6.
Next, the obtained web was passed between a flat roll and an embossing roll (pattern specification: slanted ridge pattern, pressure bonding area ratio 14%) to bond the fibers at a temperature of 135 ° C. and a linear pressure of 35 kgf / cm. / M ² long fiber nonwoven fabric was obtained.

Example 8
The length of the warp pattern was 110 mm, and a long fiber nonwoven fabric having an average single yarn fineness of 2.5 dtex and a basis weight of 15 g / m ² was obtained in the same manner as in Example 2. The obtained non-woven fabric was passed through a corona discharge treatment machine under a discharge amount of 40 W · min / m ² (discharge degree: 4.0 W / cm ² ) in an atmosphere at room temperature of 22 ° C., and a non-woven fabric having a wetting tension of 39 mN / m was obtained. Obtained.
A polyether-based hydrophilizing agent was applied to the obtained non-woven fabric by a spraying method, followed by hot air drying at 80 ° C. for 5 minutes to obtain a long-fiber non-woven fabric having a hydrophilic agent concentration adhesion amount of 0.3% by weight.

Example 9
A long-fiber nonwoven fabric having an average single yarn fineness of 2.8 dtex, a weight per unit area of 18 g / m ^{2 and} a hydrophilic agent concentration adhesion amount of 0.5% by weight was obtained in the same manner as in Example 8 with a warp pattern length of 110 mm.

Example 10
A long fiber web having an average single yarn fineness of 2.5 dtex was prepared in the same manner as in Example 7 with a warp pattern length of 60 mm.
Next, the fibers were bonded in the same manner as in Example 6 to obtain a long fiber nonwoven fabric having a basis weight of 17 g / m ² . The obtained non-woven fabric was passed through a corona discharge treatment machine under a discharge amount of 40 W · min / m ² (discharge degree: 4.0 W / cm ² ) in an atmosphere at room temperature of 22 ° C., and a non-woven fabric having a wetting tension of 39 mN / m was obtained. Obtained. A polyether-based hydrophilizing agent was applied to the obtained non-woven fabric by a kiss coater method, followed by hot air drying at 80 ° C. for 5 minutes to obtain a long-fiber non-woven fabric having a hydrophilic agent concentration adhesion amount of 0.3% by weight.

Example 11
1.25% by weight of octadecanoic acid glycerides (hydrogenated animal and vegetable oils and fats) having a melting point of 86 to 90 ° C. (average melting point of 88 ° C.) was set to a vertical pattern length of 110 mm, and the average single yarn fineness was 1 as in Example 1. A long-fiber non-woven fabric having ² dtex and a basis weight of 17 g / m ² was obtained.

Example 12
A long fiber web having an average single yarn fineness of 2.0 dtex was prepared in the same manner as in Example 2 by mixing 3.50% by weight of glycerides of octadecanoic acid (hydrogenated vegetable oil and fat), setting the vertical pattern length to 110 mm.
Next, the obtained web was passed between a flat roll and an embossing roll (pattern specification: slanted ridge pattern, pressure bonding area ratio 14%) to bond the fibers at a temperature of 135 ° C. and a linear pressure of 35 kgf / cm, and a basis weight of 15 g. / M ² long fiber nonwoven fabric was obtained.

Example 13
A general-purpose polyethylene terephthalate resin is extruded by a spunbond method at a single hole discharge rate of 0.9 g / min · Hole, a spinning temperature of 300 ° C., and this filament group is pulled using a high-speed airflow pulling device using an air jet. The long fiber web having an average single yarn fineness of 2.0 dtex was prepared by extruding toward the moving collection surface so that the pattern length was 250 mm.
Next, the obtained web was passed between a flat roll and an embossing roll (pattern specification: texture pattern, horizontal pitch 2.0 mm, vertical pitch 2.0 mm, crimping area 14.4%), and a temperature of 235 ° C. The fibers were bonded together at a pressure of 35 kgf / cm to obtain a long fiber nonwoven fabric having a basis weight of 12 g / m ² .

[Comparative Example 1]
A single fiber discharge rate of 0.22 g / min · Hole, a vertical pattern length of 110 mm, and a long fiber web having an average single yarn fineness of 1.1 dtex was obtained in the same manner as in Example 1. Next, the obtained web was passed between a flat roll and an embossing roll (pattern specification: circular with a diameter of 0.425 mm, staggered arrangement, horizontal pitch 2.1 mm, vertical pitch 1.1 mm, crimping area ratio 6.3%). Then, the fibers were bonded to each other at a temperature of 125 ° C. and a linear pressure of 15 kgf / cm to obtain a long fiber nonwoven fabric having a basis weight of 17 g / m ² .

[Comparative Example 2]
A single-hole discharge rate of 0.40 g / min · Hole, a vertical pattern length of 30 mm, and a single fiber fineness of 2.0 dtex and a fabric weight of 20 g / m ² were obtained in the same manner as in Example 1.

[Comparative Example 3]
The length of the warp pattern was 110 mm, and a long fiber web having an average single yarn fineness of 1.1 dtex was obtained in the same manner as in Example 1.
The obtained web was passed between a flat roll and an embossing roll (pattern specification: texture pattern, horizontal pitch 2.0 mm, vertical pitch 2.0 mm, crimping area 14.4%), and the temperature was linear pressure at 148 ° C. Was 50 kgf / cm, and a non-woven fabric having a basis weight of 17 g / m ² was obtained.

[Comparative Example 4]
The length of the vertical pattern was 500 mm, and a long fiber nonwoven fabric having an average single yarn fineness of 2.8 dtex and a basis weight of 11 g / m ² was obtained in the same manner as in Example 2.

The nonwoven fabric made of the thermoplastic fiber of the present invention is a nonwoven fabric having good width dimensional stability, excellent flexibility, and good workability, and is therefore suitable for use in sanitary material topsheets, backsheets, side gathers, etc. Is possible.

Claims

A nonwoven fabric made of thermoplastic fibers, wherein the fiber orientation in the nonwoven fabric is 1.05 or more and 2.0 or less in terms of the molecular orientation degree, and the 3% elongation stress of the nonwoven fabric is 2N / The nonwoven fabric characterized by being 5 cm or more and 10 N / 5 cm or less.
The nonwoven fabric according to claim 1, wherein the nonwoven fabric has a length / width ratio of 1.5 to 10 inclusive.
The nonwoven fabric according to claim 1 or 2, wherein the width dimension change of the width of the nonwoven fabric is 0% or more and 10% or less.
The nonwoven fabric according to any one of claims 1 to 3, wherein the thermoplastic fiber is a polyolefin fiber.
The nonwoven fabric according to claim 4, wherein the polyolefin fiber is a polypropylene fiber.
The nonwoven fabric according to any one of claims 1 to 5, wherein the nonwoven fabric is a long-fiber nonwoven fabric.
The nonwoven fabric according to any one of claims 1 to 6, wherein an average single yarn fineness of the thermoplastic fiber is 0.5 dtex or more and 3.5 dtex or less.
A sanitary material using the nonwoven fabric according to any one of claims 1 to 7.
9. Sanitary material according to claim 8, in the form of disposable diapers, sanitary napkins or incontinence pads.