JP2023136325A - Nonwoven fabric of long fiber, and buffer material - Google Patents

Abstract

To provide a nonwoven fabric having suppressed thickness for compactification, with good productivity.SOLUTION: The nonwoven fabric of long fiber of the present invention includes a two-component composite spun long fiber containing polyethylene terephthalate and copolyester, having a compression recovery rate of 30%.SELECTED DRAWING: None

Description

The present invention relates to a long-fiber nonwoven fabric that is not bulky, compact, and excellent for use in cushioning purposes.

For example, non-adhesive packaging materials such as paper tape, kraft paper, or wrapping paper that are easy to release are usually wrapped around the item and tied using the packaging material itself, rope, or string, or wrapped in a sheet. Fix it using adhesive tape, etc. Furthermore, if there are a large number of items to be packed, a plurality of items packed in the above manner may be further integrated and repacked. When transporting these items, extremely complicated measures are required, such as wrapping cushioning material around the outer circumferential surface of the products and inserting resin or hard materials between the products to prevent the cargo from collapsing.

In order to improve these problems, there is a packaging material made of a cylindrical knitted fabric, as disclosed in Patent Document 1, for example. Further, Patent Document 2 discloses a packaging material using a nonwoven fabric of crimped short fibers.

JP2007-182245 JP2009-184697

However, packaging materials made of tubular knitted fabrics such as those disclosed in Patent Document 1 require the preparation of knitted fabrics of different sizes depending on the dimensions of the items to be packed, and there are many types from small to large. There is a problem in that many types of packaging materials are required when trying to package several items. In addition, it is difficult to attach cords, hoses, rods, strips, straw, grass, etc. when protecting and packing the entire length, especially when there are protrusions on the surface. Very difficult.

Furthermore, since the packaging material disclosed in Patent Document 2 uses short fibers, it is difficult to reduce the thickness, and the packaging material is inferior in compactness. Furthermore, if the object to be packed is delicate, there is a possibility that it may be damaged due to the presence of fiber ends. Furthermore, since the manufacturing process becomes long, productivity is low. Spunbond nonwoven fabrics are a method that can shorten the process, but because the filaments of conventional spunbond nonwoven fabrics do not have crimps, they become too paper-like and cannot function adequately as a cushioning material.

As described above, a nonwoven fabric that can be made compact and that can sufficiently suppress damage to the protected article when used as a cushioning material or packaging material has not been known so far.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a nonwoven fabric that is a long fiber nonwoven fabric with good productivity, can be made compact, and can reduce damage to the articles it protects.

The present inventors have conducted intensive research on nonwoven fabrics that can be made compact and cause less damage to the protected items when used as cushioning materials or packaging materials, and have now completed the present invention.

That is, the present invention is as follows.
(1) A long-fiber nonwoven fabric comprising two-component composite spun long fibers containing polyethylene terephthalate and copolymerized polyester, and having a compression recovery rate of 30%.
By using a long-fiber nonwoven fabric manufacturing method such as spunbond nonwoven fabric, the amount of fiber ends can be greatly reduced, so in the case of cushioning or packaging applications, damage to the protected articles can be suppressed. In addition, by specifying the compression recovery rate, it is possible to expect an effect beyond a certain level of buffering effect.

(2) The long fiber nonwoven fabric of (1) having an apparent density of 0.1 g/cc or more.
When the apparent density is 0.1 g/cc or more, it has the advantage of being compact due to its low thickness and being able to suppress damage to the article to be protected.

(3) The long fiber nonwoven fabric according to (1) or (2), which has a coefficient of friction (MIU) of at least one side of 0.4 or less.
By satisfying the above friction coefficient, damage to the article protected by the nonwoven fabric can be suppressed.

(4) The long fiber nonwoven fabric according to any one of (1) to (3), which has a 50% elongation recovery rate of 55% or more.
When the 50% elongation recovery rate is 55% or more, it has excellent elasticity, so when used as a cushioning material or packaging material, the load on the article to be protected can be reduced.

(5) The long fiber nonwoven fabric according to any one of (1) to (4), wherein the long fibers are crimped yarns.
When the long fibers are crimped yarns, better cushioning properties can be obtained and damage to the article to be protected can be suppressed.

(6) The long fiber nonwoven fabric according to any one of (1) to (5), wherein the long fiber has a core-sheath structure.
If the long fibers have a core-sheath structure, they can be suitably crimped during production.

(7) The long fiber nonwoven fabric according to (6), wherein the core-sheath structure has a center of the core component eccentric by 2% or more.
When the center of the core component of the core-sheath structure is eccentric by 2% or more, it becomes possible to perform crimp processing more appropriately during manufacturing.

(8) The long fiber nonwoven fabric according to any one of (1) to (5), wherein the long fibers have a side-by-side structure.
When the long fibers have a side-by-side structure, they can be suitably crimped during production.

(9) The long fiber nonwoven fabric of any of the above (1) to (8) which has not been subjected to mechanical entanglement treatment.
It is preferable that the long-fiber nonwoven fabric is not mechanically entangled, since fewer fiber end faces occur. The long-fiber nonwoven fabric according to the present invention is obtained by temporarily pressing a long-fiber web containing copolymerized polyester and then crimping the web, as will be described in detail later. Amorphous polyester has a characteristic that it is difficult to be bonded up to around 130° C. and is difficult to be restrained by bonding points. Therefore, in the crimping process, expansion and contraction occurs first. Then, they can be brought into close contact with each other in a state where they are expanded and contracted. Therefore, no mechanical entangling treatment is required. In the case of a configuration in which no mechanical entangling treatment is performed, manufacturing can be done at low cost. Furthermore, compared to the case where needle punching is used as the mechanical entangling process, the risk of needles being mixed in can be avoided.

(10) The copolymerized polyester according to any one of (1) to (9), wherein the dicarboxylic acid component is terephthalic acid, and the glycol component is 50 to 85 mol% of ethylene glycol and 15 to 50 mol% of neopentyl glycol. long fiber non-woven fabric.
When the dicarboxylic acid component of the copolymerized polyester is terephthalic acid and the glycol component is 50 to 85 mol% of ethylene glycol and 15 to 50 mol% of neopentyl glycol, the crystallinity is moderately reduced and is suitable for spunbond nonwoven fabric. It is possible to develop a crimp.

Furthermore, cushioning materials or packaging materials using the long fiber nonwoven fabrics described in (1) to (10) are also included within the scope of the present invention.
It has good productivity, can be made compact, and can reduce damage to the items it protects.

The nonwoven fabric of the present invention is a long fiber nonwoven fabric with good productivity, yet can be made compact, and when used as a cushioning material or packaging material, can reduce damage to the articles to be protected.

Embodiments of the present invention will be described below.

[Spunbond nonwoven fabric]
The long-fiber nonwoven fabric according to the present embodiment is composed of two-component composite spun long fibers containing polyethylene terephthalate and copolymerized polyester, and has a compression recovery rate of 30% in the method described below.

The long fibers constituting the long fiber nonwoven fabric are composed of two-component composite spinning containing polyethylene terephthalate and copolymerized polyester. The long fiber nonwoven fabric may be a spunbond nonwoven fabric.

In this specification, long fibers refer to fibers whose length during spinning is endless (endless continuous fibers). However, when the finally obtained long fiber nonwoven fabric is cut into a predetermined length, the length of the long fibers is the same as the length of the long fiber nonwoven fabric. On the other hand, short fibers refer to fibers contained in a nonwoven fabric whose length is less than the length of the nonwoven fabric. In other words, a long fiber nonwoven fabric is a nonwoven fabric composed of fibers (long fibers) having the same length as the length of the nonwoven fabric, and a short fiber nonwoven fabric is a nonwoven fabric composed of fibers (short fibers) whose length is less than the length of the short fiber nonwoven fabric. A nonwoven fabric made of

Since the long fibers contain polyethylene terephthalate, they are superior in mechanical strength, heat resistance, shape retention, etc. compared to cases where resins such as polyethylene and polypropylene are used. The content ratio of the polyethylene terephthalate in the long fibers is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less. When the content ratio of the polyethylene terephthalate is within the above numerical range, mechanical strength, heat resistance, shape retention, etc. are better. Note that polyethylene terephthalate is a polyester that exhibits an exothermic peak derived from crystallization and/or an endothermic peak derived from crystal melting when measured using a differential scanning calorimeter (DSC).

The amorphous polyester is a resin that does not have a clear crystallization exothermic peak or crystal melting peak when measured using a differential scanning calorimeter (DSC). Further, the amorphous polyester has a glass transition temperature (Tg) of 50°C or higher. The glass transition temperature (Tg) is a value determined by DSC from the latent heat transition point during temperature increase at a temperature increase rate of 20° C./min. By employing, as the amorphous polyester, a polyester having a glass transition temperature (Tg) of 50° C. or higher, good heat resistance can be obtained. That is, in the long fiber nonwoven fabric, in order to improve heat resistance and impact resistance, the copolyester polyester, which is amorphous but has a high Tg, is used.

Further, the copolymerized polyester has lower crystallinity than polyethylene terephthalate (homopolymer). The spunbond nonwoven fabric (the long fibers) is a two-component composite spun yarn containing polyethylene terephthalate and copolymerized polyester, so when it is heat treated, there is a difference in the amount of shrinkage due to the difference in crystallinity. Shrinkage occurs.

The copolymerization components of the copolymerized polyester include dicarboxylic acid components such as aromatic dicarboxylic acids such as terephthalic acid and 2,6-naphthalene dicarboxylic acid; oxalic acid, succinic acid, adipic acid, sebacic acid, undecadicarboxylic acid, etc. Aliphatic dicarboxylic acids; include alicyclic dicarboxylic acids such as hexahydroterephthalic acid; glycol components include aliphatic glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, hexamethylene glycol; Examples include aromatic glycols such as bisphenol, 1,3-bis(2-hydroxyethoxy)benzene, and 1,4-(hydroxyethoxy)benzene. These can be used alone or in combination of two or more. The copolymerization component is preferably selected within a range that allows the Tg of the copolyester to be maintained at 50°C or higher.

Among the above copolymerized polyesters, the following (a) to (d) are preferable, and (a) is more preferable.
(a) A copolymerized polyester in which the dicarboxylic acid component is terephthalic acid and the glycol components are 50 to 85 mol% of ethylene glycol and 15 to 50 mol% of neopentyl glycol.
(b) A copolymerized polyester in which the dicarboxylic acid component is terephthalic acid and the glycol component is 50 to 85 mol % of ethylene glycol and 15 to 50 mol % of 1,4-cyclohexanedimethanol.
(c) A copolymerized polyester in which the dicarboxylic acid component is terephthalic acid and the glycol components are 50 to 85 mol% of 1,4-butanediol and 15 to 50 mol% of neopentyl glycol.
(d) A copolymerized polyester in which the dicarboxylic acid component is terephthalic acid and the glycol component is 50 to 85 mol% of 1,4-butanediol and 15 to 50 mol% of 1,4-cyclohexanedimethanol.
In the case of (a) and (b) above, the content of ethylene glycol is more preferably 50 to 85 mol%, and even more preferably 65 to 75 mol%.
In the case of (c) and (d) above, the content of 1,4-butanediol is more preferably 50 to 85 mol%, and even more preferably 65 to 75 mol%.
In the cases of (a) and (c) above, the content of neopentyl glycol is more preferably 15 to 50 mol%, and even more preferably 25 to 35 mol%.
In the case of (b) and (d) above, the content of 1,4-cyclohexanedimethanol is more preferably 15 to 50 mol%, and even more preferably 25 to 35 mol%.
The copolyesters (a) to (d) have moderately reduced crystallinity and can develop crimp suitable for spunbond nonwoven fabrics. Further, properties such as thermal stability are preferable.

The content ratio of the copolymerized polyester in the long fibers is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and still more preferably 40% by mass or more and 60% by mass or less. When the content ratio of the copolyester is within the numerical range, crimp can be suitably developed.

The copolymerization method for producing the copolymerized polyester is not particularly limited, and conventionally known methods can be employed.

The long fibers preferably have a core-sheath structure. When the long fibers have a core-sheath structure, they can be suitably crimped during production.

Preferably, the core-sheath structure has an eccentric fiber cross section. Specifically, the center of the core component is preferably eccentric by 2% or more, and more preferably by 3% or more. That is, the eccentricity measured by the method described in Examples is preferably 2% or more, more preferably 3% or more. The eccentricity of the center of the core component is preferably as large as possible, and can be set to, for example, 80% or less, 60% or less.

In the core-sheath structure, from the viewpoint of obtaining suitable crimp, it is preferable that the sheath side is made of copolymerized polyester and the core side is made of polyethylene terephthalate.

The long fibers may have a side-by-side structure in which copolymerized polyester and polyethylene terephthalate are bonded together. When the long fibers have a side-by-side structure, they can be suitably crimped during production.

The fiber diameter of the long fibers is preferably 5 to 60 μm, more preferably 10 to 50 μm, and still more preferably 12 to 40 μm. When the fiber diameter is 5 μm or more, when the long fiber nonwoven fabric is a spunbond nonwoven fabric, the spinnability in the spunbond method becomes better and stable production becomes possible. Moreover, when the fiber diameter is 60 μm or less, unevenness of the nonwoven fabric is less likely to deteriorate, and excellent appearance quality can be obtained.

It is preferable that the long fiber nonwoven fabric is not subjected to mechanical entanglement treatment. Examples of the mechanical entanglement treatment include entanglement treatment using a needle punch method and a water punch method. It is preferable that the mechanical entanglement treatment is not performed because it can be manufactured at low cost. It is also preferable in that it is possible to avoid the risk of contamination with needles that may occur when the needle punch method is employed. Furthermore, the water punch method uses a large amount of water and requires a huge amount of energy. Therefore, from the viewpoint of environmental preservation and energy saving, it is preferable that the mechanical entanglement treatment is not performed.

It is preferable that the long fiber nonwoven fabric has a compression recovery rate of 30% or more. Measurement of compression recovery rate will be described later. When the compression recovery rate is 30% or more, when used as a packaging material or a cushioning material, a certain cushioning effect on the article to be protected can be expected. It is preferable that the apparent density is 0.1 g/cc or more. The apparent density is preferably as large as possible, and may be, for example, 0.3 g/cc or less, 0.28 g/cc or less, etc. If the apparent density is above a certain level, the appearance will be good.

The long fiber nonwoven fabric has an elongation of 50% or more, preferably 70% or more, and more preferably 90% or more. Moreover, since the elongation is 50% or more, it has excellent moldability and can be formed into complex shapes.
In this specification, "elongation is 50% or more" means that the elongation in the MD (machine direction) direction is 50% or more and the elongation in the CD (cross direction) direction is 50% or more. say something.

It is preferable that the long fiber nonwoven fabric has a coefficient of friction (MIU) of at least one side of 0.4 or less. By satisfying the above friction coefficient, damage to the article protected by the long fiber nonwoven fabric can be suppressed.

The long fiber nonwoven fabric preferably has an elongation recovery rate at 50% elongation (50% elongation recovery rate) of 55% or more. Measurement of 50% elongation recovery rate will be explained later. When the 50% elongation recovery rate is 55% or more, it has excellent elasticity, so when used as a cushioning material or packaging material, the load on the article to be protected can be reduced.

The long fiber nonwoven fabric according to this embodiment has been described above. Next, a method for manufacturing a spunbond nonwoven fabric will be described as an example of the long fiber nonwoven fabric according to the present embodiment.

[Method for manufacturing spunbond nonwoven fabric]
The method for producing the spunbond nonwoven fabric according to the present embodiment is to eject molten polyethylene terephthalate and copolymerized polyester from a spinneret, cool and solidify them, and then pull and stretch them using an ejector to form a two-component composite spun yarn. Step A of forming long fibers, Step B of collecting the long fibers obtained in step A to form a long fiber web, Step C of temporarily pressing the long fiber web, and step C of temporarily pressing the long fiber web. and step D of crimping the long fiber web.

<Process A>
In the method for producing a spunbond nonwoven fabric according to the present embodiment, first, melted polyethylene terephthalate and copolymerized polyester are discharged from a spinneret, cooled and solidified, and then pulled and stretched by an ejector to form two components. Forms composite spun filaments.

This step A can be carried out using a conventionally known two-component spunbond spinning machine. That is, the long fibers can be manufactured by the spunbond method, which is a direct spinning type manufacturing method in which a nonwoven fabric is manufactured directly from the fiber manufacturing process (spinning process).

As the polyethylene terephthalate and the copolymerized polyester, those explained in the section of the spunbond nonwoven fabric above can be used.

In the step A, it is preferable to perform spinning at a spinning speed of 3500 m/min or more. In other words, molten polyethylene terephthalate and copolymerized polyester are discharged from a spinneret, cooled and solidified, and then pulled and stretched by an ejector at a spinning speed of 3,500 m/min or higher to form two-component composite spun filaments. It is preferable to do so. By setting the spinning speed to 3500 m/min or more, the degree of oriented crystallinity of polyester terephthalate becomes high. When the spinning speed is set to 3500 m/min or more, the orientation of the copolyester also progresses. However, since copolyester has low crystallinity, the component on the copolyester side will shrink in the subsequent crimping process (heating process in step D), and crimping may not be suitable. manifest. The spinning speed is more preferably 3800 m/min or more, and still more preferably 4200 m/min or more. Further, from the viewpoint of spinnability, the spinning speed is preferably 5,500 m/min or less, more preferably 5,000 m/min or less.

In this specification, the spinning speed refers to a value obtained by the following formula (1).
V=(10000×Q)/T (1)
Here, V is the spinning speed (m/min), T is the fineness of the single fiber (dtex), and Q is the single-hole discharge rate (g/min).

The single hole discharge amount Q is the total of the two components, and is preferably 0.2 to 5 g/min. By controlling the single hole discharge rate Q to 0.2 to 5 g/min, it becomes easier to control the spinning speed V within a desired range. More preferably 0.3 to 4 g/min, more preferably 0.5 to 3 g/min. Note that the fineness T (dtex) of a single fiber is a value representing the mass of a 10,000 meter single fiber in grams.

In step A, an eccentric core-sheath nozzle is used as the spinneret, and step A-1 of discharging the polyethylene terephthalate as a core component and the copolymerized polyester as a sheath component from the eccentric core-sheath nozzle. It is preferable to include. As the eccentric core-sheath nozzle, a conventionally known one can be employed. When an eccentric core-sheath nozzle is used as the spinneret and the polyethylene terephthalate as a core component and the copolymerized polyester as a sheath component are discharged from the eccentric core-sheath nozzle, a subsequent crimping process (step D) is performed. In this case, it becomes possible to suitably perform crimp processing.

The step A includes a step A-2 of using a side-by-side nozzle as the spinneret and discharging the polyethylene terephthalate and the copolymerized polyester from the side-by-side nozzle so as to bond them side-by-side in the fiber length direction. It is also preferable. A conventionally known side-by-side nozzle can be used as the side-by-side nozzle. When a side-by-side nozzle is used as the spinneret and the polyethylene terephthalate and the copolymerized polyester are discharged from the side-by-side nozzle so as to be laminated side-by-side in the fiber length direction, the subsequent crimping step (step D) is suitable. It becomes possible to apply crimping to the material.

In the step A, it is preferable to adopt either the step A-1 or the step A-2.

Regardless of whether the above process A-1 or the above process A-2 is adopted, the spinneret is spun from a spinneret with an orifice diameter of 0.1 to 0.5 mm, and the ejector is fed with a weight of 1.5 to 4.0 kg/cm ^{2 .} It is preferable to supply dry air at a pressure (jet pressure) of The orifice diameter of the spinneret is more preferably 0.15 to 0.45 mm, and even more preferably 0.18 to 0.45 mm. The jet pressure is more preferably 2.0 to 4.0 kg/cm ² , even more preferably 2.5 to 3.8 kg/cm ² . By controlling the orifice diameter within the above range, it becomes easier to obtain a desired fiber diameter. Furthermore, by controlling the drying air supply pressure (jet pressure) within the above range, it becomes easier to control the spinning speed within a desired range, and it is possible to dry the fiber appropriately.

<Process B>
Next, the long fibers obtained in step A are collected to form a long fiber web (step B). For example, a long fiber web may be formed by collecting the long fibers while opening them onto a conveyor below.

<Process C>
Next, the long fiber web obtained in the step B is temporarily pressed (step C). The temporary pressure bonding is performed within a temperature range in which the long fiber web does not shrink. Thereby, it becomes possible to convey it suitably. The temperature during the temporary pressure bonding is preferably 50°C to 80°C, more preferably 55°C to 75°C, and still more preferably 60°C to 70°C. A flat roll can be used for the temporary pressure bonding. The linear pressure during temporary pressure bonding is preferably 1 to 10 kg/cm, more preferably 3 to 7 kg/cm. When the linear pressure is within the numerical range, the film can pass through the process without being broken during conveyance.

<Process D>
Next, the temporarily crimped long fiber web is crimped (Step D). The long fibers that have been crimped become crimped yarns. This process can be achieved by applying heat to the long fiber web, and although there are no particular limitations, treatment with hot air such as air through, treatment by contacting with a heated roller, treatment with hot water or steam, etc. are preferably adopted. Ru. The crimp method will be explained below.

In the method using heated rollers, two or more heated rollers whose temperature can be modulated and whose speed ratio can be changed are used to crimp the long fiber web while gradually lowering the speed ratio. The heating roller is set at or above the temperature at which crimping occurs, and shrinkage also occurs. However, in this embodiment, the crimping process is performed while gradually reducing the speed ratio. Since the conveyance speed ratio is lowered by the amount of shrinkage due to shrinkage, it is possible to suppress the occurrence of wrinkles caused by rapid shrinkage.

The number of heating rollers is preferably two or more, and more preferably four or more. By using a plurality of heating rollers and gradually lowering the speed ratio, the area of the long fiber web can be reduced in accordance with the amount of shrinkage, and wrinkles can be suppressed. The upper limit of the number of heating rollers is not particularly limited, but from the viewpoint of equipment cost, it may be set to, for example, 12 or less, 10 or less, etc.

The heating temperature (temperature of the heating roller) during crimping is preferably 60 to 150°C, more preferably 70 to 140°C, even more preferably 80 to 130°C. When the heating temperature is within the numerical range, crimp can be suitably developed. The conveyance speed may be slowed down depending on the amount of shrinkage of the long fiber web during crimping.

During the crimping process, nipping may be performed if necessary. It is preferable that the nip is performed at the time of crimp processing using a heated roller having the highest temperature. Adhesion can be improved by performing a nip during the crimp process using the heated roller that has the highest temperature.

The hot water treatment method involves immersing the long fiber web in boiling water at 80° C. or higher. The temperature of the boiling water is not particularly limited as long as it is 80°C or higher, but is preferably 85°C or higher, and more preferably 90°C or higher. The temperature of the boiling water is preferably 99°C or lower, more preferably 97°C or lower, from the viewpoint of suppressing wrinkles caused by rapid contraction. Since the temperature of the boiling water is 80° C. or higher, the long fibers can be suitably crimped.

The immersion time in the boiling water is not particularly limited, but is preferably 2 seconds or more, more preferably 3 seconds or more. If the immersion time in the boiling water is 5 seconds or more, sufficient crimp processing can be performed. From the viewpoint of productivity, the immersion time in the boiling water can be, for example, 20 seconds or less, 10 seconds or less, etc. The water used in the boiling water is not particularly limited, but a liquid that imparts hydrophilicity may be mixed therein to improve the impregnation rate, and an appropriate amount of a neutral detergent or the like may be added in consideration of the environment. Preferably, no tension is applied in the transverse direction while the long fiber web is immersed in the boiling water. By not applying tension in the lateral direction, the bulk density can be further increased.

The method for producing a spunbond nonwoven fabric according to the present embodiment may include, after the step D, a step E of stretching the long fiber web in the transverse direction. After the step D, when the long fiber web is stretched in the transverse direction, a spunbond nonwoven fabric having a thickness corresponding to the stretching ratio is obtained. That is, the thickness of the resulting spunbond nonwoven fabric can be adjusted by adjusting the stretching ratio in the transverse direction.

As the stretching method in the step E, stretching using a conventionally known tenter is preferred.
The stretching ratio in the transverse direction in the step E is preferably 2% or more, more preferably 5% or more. Further, the stretching ratio is preferably 20% or less, more preferably 15% or less.

In addition, in this specification, the stretching ratio in the lateral direction refers to the stretching ratio with respect to the lateral width before stretching. That is, the width after stretching is the width obtained by adding the stretching ratio to 100% of the width before stretching. For example, when the stretching ratio is 10%, the width after stretching is 110% of the width before stretching.

The method for producing a spunbond nonwoven fabric according to the present embodiment may include, after the step E, a step F of calendering the long fiber web. When the long-fiber web is calendered after the step E, the thickness of the obtained long-fiber nonwoven fabric can be adjusted more suitably by adjusting the distance between the rolls of the calendering process. Further, the thickness can be made uniform.

The distance between the rolls in the calendering process in step F is preferably 0.1 mm or more, more preferably 0.2 mm or more. When the distance between the rolls in the calendar processing in step E is 0.1 mm or more, it is possible to suppress the deterioration of the elastic function and the increase in the initial tensile stress due to excessive compression of the fibers. The distance between the rolls is preferably 0.7 mm or less, more preferably 0.5 mm or less, from the viewpoint of suitably adjusting the thickness of the obtained long fiber nonwoven fabric.

The calender temperature (roll temperature) in the step F is preferably 40°C or higher, more preferably 50°C or higher. By setting the calender temperature to 40° C. or higher, the thickness of the spunbond nonwoven fabric can be adjusted more suitably. Further, the thickness can be made more uniform.

An example of the method for manufacturing a long fiber nonwoven fabric according to the present embodiment has been described above.
Packing materials or cushioning materials using the long fiber nonwoven fabric according to this embodiment are also included within the scope of the present invention.

Hereinafter, the present invention will be described in detail using Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

(intrinsic viscosity)
Weighed 0.1 g of resin (polyethylene terephthalate or copolymerized polyester), dissolved it in 25 ml of a mixed solvent of phenol/tetrachloroethane (60/40 (weight ratio)), and dissolved it at 30°C using an Ostwald viscometer. The measurement was performed three times and the average value was determined.

(Glass transition temperature (Tg))
The glass transition temperature of the copolyester was determined according to JIS K7122 (1987) at a heating rate of 20° C./min.

(Weight)
The mass per unit area was measured according to JIS L1913 (2000) 5.2.

(thickness, apparent density (bulk density))
The above basis weight and thickness determined in accordance with JIS-L1913 (2010) 5.2 were converted into weight per 1 cm ³ to obtain the bulk density. Specifically, the thickness was measured using a 0.5 g/cm ² terminal with a thickness measuring device, and the bulk density was determined by dividing the basis weight by the thickness.

(fiber diameter)
Five arbitrary points on the sample (long fiber web before temporary compression bonding) were selected, and the diameters of the single fibers were measured using an optical microscope at n=20, and the average value was determined.

(Fineness (dtex))
Five arbitrary points on the sample (long fiber web before temporary compression bonding) were selected, and the single fiber diameter was measured using an optical microscope at n=20 to determine the average single fiber diameter. Fibers were taken out from the same five points, and the specific gravity of the fibers was measured using a density gradient tube (n=5) to determine the average specific gravity. Next, the fineness [dtex], which is the fiber weight per 10,000 m, was determined from the single fiber cross-sectional area determined from the average single fiber diameter and the average specific gravity.

(eccentricity)
A metal plate with holes of 0.5 to 2 mm was prepared. In addition, fibers constituting the nonwoven fabric were cut out and embedded in black fibers. Fibers constituting a nonwoven fabric embedded with black fibers were stuffed into the holes of the metal plate, and both ends were cut with a razor. The radius (R) of the outer circle on the sheath side was measured using an optical microscope connected to a computer equipped with distance measurement software. The distance between the center on the core side and the center on the sheath side was measured, and this was defined as the eccentric distance (L). Next, the eccentricity (%) was determined using the following formula.
(Eccentricity) = (L/R) x 100

(Spinning speed (m/min))
The spinning speed V (m/min) was determined based on the following formula from the fineness T (dtex) and the set single hole discharge amount Q (g/min).
V=(10000×Q)/T

(Elongation recovery rate at 50% elongation)
A sample of 25 x 150 mm was prepared. Using a constant speed elongation type tensile testing machine with a self-recording device, the test piece was attached at a grip interval of 50 mm while being pulled by hand to the extent that it would not loosen, and the initial load was set to 0.02 N/25 mm. At this time, "(grabbing interval) + (length extended when initial load is applied)" was defined as L0. Thereafter, it was stretched to 50% of the grip distance (25 mm elongation) at a stretching speed of 25 mm/min. The length at this time was defined as L1. Thereafter, the sample length was immediately unloaded at the same speed to the initial load and was designated as L2. The elongation recovery rate at 50% elongation was determined by the following formula. Measurements were made with n=5 in each of the vertical and horizontal directions, and the average value was rounded to the first decimal point.
Elongation recovery rate at 50% elongation (%) = [(L1-L2)/(L1-L0)] x 100

<Compression recovery rate>
A KES-FB3-A compression tester (Kato Tech) was used. A test piece of 20 cm x 20 cm was taken, compressed at a speed of 50 sec/mm (pressure area: 2 cm2), and the thickness was measured at a load of 0.5 gf/cm ² , then the thickness at 50 gf/cm ² was measured. Next, the applied pressure was removed at a speed of 50 sec/mm, and the thickness was measured again under a load of 0.5 gf/cm ² . The compression recovery rate was calculated by applying this result to the following formula.

Compression recovery rate % = (T ₀ '-T ₁ )/(T ₀ -T ₁ ) x 100
Here, T ₀ : Thickness (mm) when first multiplied by 0.5 gf/cm ²
T ₁ : Thickness when adding 50 gf/cm ² (mm)
T ₀ ': Thickness when pressure is removed and 0.5gf/ ^cm2 is applied again (mm)

(Friction characteristics: MIU)
It was measured by the following method.
Environment: 20℃ x 65%RH
Equipment: Friction tester KES-SE (Kato Tech)
Friction element: 10mm square piano wire (standard)
Friction SENS:H
Load: No additional load = 25g/cm2 (weight of friction element only)
Speed: 1mm/s
The mean coefficient of friction (MIU) is an indicator of surface flexibility. MIU is preferably 0.4 or less because the smaller the MIU value, the easier it is to feel smoothness and to provide a surface material with excellent tactility.

(Example 1) Using a core-sheath nozzle with an eccentricity of 0.1 mm in two-component spunbond spinning equipment, polyethylene terephthalate (intrinsic viscosity (IV value): 0.63) and copolymerized polyester (dicarboxylic acid component is terephthalate) were used. A copolymer whose glycol components are 70 mol% ethylene glycol and 30 mol% neopentyl glycol, intrinsic viscosity (IV value): 0.75, Tg: 75°C) of 6.5:3.5. Spun in proportion. Spinning was performed from a spinneret with an orifice diameter of 0.36 mm at a single hole discharge rate of 1.0 g/min. After that, dry air is further supplied to the ejector at a pressure of 3.5 kg/cm ² (jet pressure), and the fibers are stretched in one step and collected while opening them onto the conveyor below to form a long fiber web. I got it. Next, the obtained long fiber web was temporarily pressed. The conditions for the temporary pressure bonding were a temporary pressure bonding roll temperature of 60° C. and a linear pressure of 5 kg/cm.
The long fiber web obtained as described above had a fiber diameter of 14.5 μm, a spinning speed of 4500 m/min, and a basis weight of 25 g/m ² .

Next, the obtained long fiber web was immersed in 90°C water for 5 seconds. Note that no tension was applied in the lateral direction during immersion in boiling water. After dipping, the long fiber web was stretched in the transverse direction at a stretching ratio of 5%. Further, the spunbond nonwoven fabric (long fiber nonwoven fabric) of Example 1 was subjected to calendering at a calender temperature (roll temperature) of 60°C and a distance between the rolls of 0.2mm and dried at 110°C. Obtained.
Table 1 shows the results of measuring the physical properties of the spunbond nonwoven fabric thus obtained.

It can be seen that the spunbond nonwoven fabric of Example 1 is suitable for use in cushioning or packaging applications.

The long-fiber nonwoven fabric of the present invention is a long-fiber nonwoven fabric with good productivity, has a suppressed thickness, can contribute to compactness, is useful, for example, when used as a packaging material for articles, and can greatly contribute to industry.

Claims (12)

A long fiber nonwoven fabric comprising two-component composite spun long fibers containing polyethylene terephthalate and copolymerized polyester, and having a compression recovery rate of 30%. The long fiber nonwoven fabric according to claim 1, having an apparent density of 0.1 g/cc or more. The long fiber nonwoven fabric according to claim 1 or 2, characterized in that the coefficient of friction (MIU) on at least one side is 0.4 or less. The long fiber nonwoven fabric according to any one of claims 1 to 3, which has a 50% elongation recovery rate of 55% or more. The long fiber nonwoven fabric according to any one of claims 1 to 4, wherein the long fibers are crimped yarns. The long fiber nonwoven fabric according to any one of claims 1 to 5, wherein the long fibers have a core-sheath structure. 7. The long fiber nonwoven fabric according to claim 6, wherein the core-sheath structure has a center of the core component eccentric by 2% or more. The long fiber nonwoven fabric according to any one of claims 1 to 5, wherein the long fibers have a side-by-side structure. The long fiber nonwoven fabric according to any one of claims 1 to 8, which is not subjected to mechanical entanglement treatment. Any one of claims 1 to 9, wherein the dicarboxylic acid component of the copolymerized polyester is terephthalic acid, and the glycol component is 50 to 85 mol% of ethylene glycol and 15 to 50 mol% of neopentyl glycol. The long fiber nonwoven fabric described in . A cushioning material using the long fiber nonwoven fabric according to any one of claims 1 to 10. A packaging material using the long fiber nonwoven fabric according to any one of claims 1 to 10.