JP6995462B2 - Fiber sheet with excellent flexibility - Google Patents

Description

The present invention relates to a fiber sheet that can be suitably used as a bandage or the like.

Bandages are not only used to wrap around the application site, such as the affected area, to directly protect the application site, or to secure other protective members (such as gauze) to the application site, but also if they have elasticity. It is also used to stop bleeding in wounds by applying pressure during wrapping using its elasticity, and to promote blood flow to improve swelling. In recent years, it has also been applied to compression therapy in which treatment is performed by compressing the affected area, such as treatment / improvement of varicose veins of the lower extremities.

As a method of giving elasticity to the bandage, 1) a thread made of an elastic material such as an elastomer typified by rubber is woven into the fabric, and 2) a layer made of an elastic material such as an elastomer is added to the non-stretchable fabric. It has been conventionally known to combine or impregnate an elastic material, and many elastic bandages using such a method are commercially available.

For example, Japanese Patent No. 3743966 (Patent Document 1) describes an elastic bandage in which elasticity is imparted in the length direction by using an elastic thread as a warp (warp). Further, in Patent No. 5600119 (Patent Document 2), an elastic nonwoven fabric fiber web to which elasticity is imparted by a method of entwining a nonwoven fabric fiber with an elastic filament in an elongated state and then relaxing the stretched state of the elastic filament. Is described. Japanese Patent Application Laid-Open No. 2014-515320 (Patent Document 3) impregnates an elastic composite article containing a non-woven fabric fibrous cover web, a woven fabric scrim, and a plurality of elastic threads arranged between them with an elastomer polymer binder. Described are composite articles having elasticity and self-adhesiveness.

Japanese Patent No. 3743966 Japanese Patent No. 5600119 Japanese Patent Publication No. 2014-515320

When applying a bandage to a site that bends and stretches, such as a joint, the elasticity of the bandage is certainly advantageous in increasing the bendability (movability) of the joint. However, there was still room for improvement in the flexibility of joints, especially the flexibility of small joints such as fingers.

Therefore, an object of the present invention is to provide a fiber sheet that does not easily hinder the bending operation of the site even if it is wrapped around a site that bends and stretches, such as a joint portion, and a bandage using the fiber sheet.

The present invention provides the following fiber sheets and bandages.
[1] When the thickness of one sheet measured according to the method A of JIS L 1913 is T ₁ [mm], and the thickness of three sheets measured under the same conditions is T ₃ [mm]. , The following formula:
{T ₃ / (3 x T ₁ )} x 100 ≤ 85 [%]
Meet, fiber sheet.

[2] The stress at elongation when elongated at an elongation rate of 50% in the first direction in the plane is 50% stress at elongation S ₁ [N / 50 mm], in the second direction orthogonal to the first direction in the plane. When the stress at elongation when elongated at an elongation rate of 50% is 50% stress at elongation S ₂ [N / 50 mm], the following formula:
S ₂ / S ₁ ≧ 3
The fiber sheet according to [1], which satisfies the above conditions.

[3] Has a length direction and a width direction,
The fiber sheet according to [2], wherein the first direction is the width direction.

[4] The fiber sheet according to any one of [1] to [3], which has a basis weight of 50 g / m ² or more.

[5] The fiber sheet according to any one of [1] to [4], wherein the compressive elastic modulus measured according to JIS L 1913 is 85% or less.

[6] The fiber sheet according to any one of [1] to [5], wherein the curved surface slip stress is 3 to 30 N / 50 mm.

[7] The fiber sheet according to any one of [1] to [6], which is a non-woven fabric sheet.
[8] The fiber sheet according to [7], which comprises crimped fibers.

[9] The fiber sheet according to any one of [1] to [8], which is a bandage.

According to the present invention, it is possible to provide a fiber sheet that does not easily hinder the bending operation of a portion such as a joint portion that is bent and stretched, and a bandage using the same.

It is a schematic diagram which shows the method of preparing a sample for measuring a curved surface slip stress. It is sectional drawing which shows the sample for measuring the curved surface slip stress. It is a schematic diagram which shows the measuring method of a curved surface slip stress.

(1) Characteristics of Fiber Sheet The fiber sheet according to the present invention (hereinafter, also simply referred to as “fiber sheet”) is a medical article such as a compression bandage used for bleeding stoppage and compression therapy, in addition to a general bandage. It is a fiber sheet that can be suitably used as. The thickness of one sheet measured according to JIS L 1913 A method (load: 0.5 kPa) is T ₁ [mm], and the thickness of three sheets measured under the same conditions is T ₃ [mm]. ], The fiber sheet shall have the following formula [A]:
{T ₃ / (3 × T ₁ )} × 100 ≦ 85 [%] [A]
Meet.

Even if the fiber sheet satisfying the above formula [A] is wound around a bending and stretching portion such as a joint portion, it is unlikely to hinder the bending operation of the portion. If the site is a small joint such as a finger, the difficulty of movement when wrapped with a bandage becomes particularly remarkable, but according to the fiber sheet satisfying the above formula [A], such a small joint Even when it is wound around the portion, it is possible to effectively suppress that the bending operation is hindered. From the viewpoint of ease of bending of the portion when it is wound around the portion to be bent and stretched, the left side of the above formula [A] is preferably 84% or less, more preferably 83% or less. The left side of the above formula [A] is usually 50% or more, and more typically 60% or more.

As another means for suppressing the inhibition of the bending operation, it is conceivable to reduce the basis weight of the fiber sheet. However, if the basis weight is reduced, the strength of the fiber sheet is reduced, and sufficient durability is obtained, for example, the wear resistance of the exposed outer portion when wrapped around the application site is reduced, and the fiber sheet is easily broken during elongation. It becomes difficult. On the other hand, according to the fiber sheet satisfying the above formula [A], it is possible to suppress the inhibition of the bending operation regardless of the adjustment of the basis weight. Therefore, according to the present invention, it is possible to provide a fiber sheet that can suppress the inhibition of bending operation and has good durability.

The fiber sheet preferably has extensibility from the viewpoint of ease of bending of the portion when it is wound around the portion to be bent and stretched. As used herein, "having extensibility" means exhibiting 50% elongation stress in at least one direction (first direction) within the sheet surface. The 50% elongation stress is the elongation stress (immediately after elongation) when elongated at an elongation rate of 50%, and is measured by a tensile test according to JIS L 1913 "general nonwoven fabric test method".

When the fiber sheet is a bandage having, for example, a length direction and a width direction, and it is assumed that the bandage is wrapped around a joint portion such as a finger, the bandage is generally parallel to the width direction and the length direction of the finger. Or they are wound so that they are approximately parallel. In this case, in order to improve the bendability of the knuckle portion, it is preferable that the bandage has good extensibility at least in the width direction. From this point of view, the first direction is preferably the width direction of the fiber sheet when the fiber sheet has a length direction and a width direction such as a bandage. This width direction can be a direction orthogonal to the flow direction (MD direction) of the fiber sheet in the manufacturing process, that is, the CD direction.

As described above, the fiber sheet is preferably excellent in at least one direction (first direction) in the sheet surface, more preferably in the width direction, and specifically, is stretched in the first direction at an elongation rate of 50%. Elongation stress is 50% Elongation stress S ₁ [N / 50mm], Elongation stress is 50% Elongation stress when Elongation is 50% in the second direction orthogonal to the first direction in the plane. When the stress S ₂ [N / 50 mm], the following formula [B]:
S ₂ / S ₁ ≧ 3 [B]
It is preferable to satisfy. The left side of the above formula [B] is preferably 5 or more. The left side of the above equation [B] is usually 20 or less. According to the fiber sheet having the first direction satisfying the above formula [B], the bending operation is hindered in the usage mode in which the first direction and, for example, the length direction of the finger are wound so as to be parallel or substantially parallel. It can be suppressed more effectively. The left side of the above formula [B] is preferably 10 or less from the viewpoint of imparting relatively good extensibility even in the second direction.

The 50% elongation stress S ₁ in the first direction is preferably 0.1 to 20 N / 50 mm, more preferably 0.5 to 15 N / 50 mm, still more preferably 1 to 12 N / 50 mm.

When the fiber sheet has a length direction and a width direction, the second direction orthogonal to the first direction in the plane is preferably the length direction. The length direction can be the flow direction (MD direction) of the fiber sheet in the manufacturing process. The 50% elongation stress S ₂ in the second direction and the 50% elongation stress in other directions other than the first direction are preferably 0.5 to 60 N / 50 mm, more preferably 1 to 45 N / 50 mm, respectively. It is preferably 2 to 40 N / 50 mm.

The fiber sheet preferably exhibits self-adhesiveness. As used herein, the term "self-adhesiveness" refers to the property that fibers on the surface of a fiber sheet can be hooked or fixed by being engaged with or in close contact with each other by overlapping (contact) with each other. Having self-adhesiveness is advantageous when the fiber sheet is a bandage or the like. For example, when the fiber sheet is a bandage, the wrapped fiber sheets are wound together by wrapping the bandage around the application site and then stacking (or tearing it off) the end portion on the surface of the bandage underneath. It is pressed while being stretched, and the fiber sheets are joined and fixed to each other to develop self-adhesiveness.

Since the fiber sheet itself has self-adhesiveness, a stopper for forming a layer made of a self-adhesive such as an elastomer or an adhesive on the surface of the fiber sheet and fixing the tip after winding is prepared separately. There is no need to do it. For example, in Japanese Patent Application Laid-Open No. 2005-095381 (Patent Document 4), an acrylic polymer (claim 1) or latex (paragraphs [0004] to [0006]) is attached as a self-adhesive to at least one surface of a bandage base material. It is stated that it should be done. Forming a layer made of an elastomer such as latex on the surface of the fiber sheet is effective in enhancing self-adhesiveness.

However, the fiber sheet according to the present invention is preferably composed only of a non-elastomer material, and more specifically, it is preferably composed only of fibers. When such a layer made of an elastomer is formed on the surface of the fiber sheet, the voids on the surface of the fiber sheet are sealed with the elastomer, so that the fibers are less likely to engage with each other when the fiber sheets are overlapped with each other. The thickness T ₃ when three sheets are stacked is not sufficiently reduced, and as a result, it tends to be relatively difficult to satisfy the above formula [A]. In addition, the layer made of elastomer may induce skin irritation and allergies when wrapped around the application site.

The self-adhesiveness of the fiber sheet can be evaluated by the curved surface sliding stress. From the viewpoint of self-adhesiveness, the fiber sheet preferably has a curved surface sliding stress of, for example, 3N / 50 mm or more, preferably 5N / 50 mm or more, and a curved surface sliding stress larger than the breaking strength. Further, when desired, the curved surface slip stress is preferably 30 N / 50 mm or less, more preferably 25 N / 50 mm or less, because it is relatively easy to unwind the wound fiber sheet. The curved surface slip stress is measured using a tensile tester according to the method described in the section of Examples (FIGS. 1 to 3).

The fiber sheet preferably has hand-cutting property. As used herein, the term "hand-cutting property" refers to the property of being able to break (cut) by pulling by hand. The hand-cutting property of the fiber sheet can be evaluated by the breaking strength. From the viewpoint of hand-cutting property, the fiber sheet has a breaking strength in at least one direction in the sheet surface, preferably 5 to 100 N / 50 mm, more preferably 8 to 60 N / 50 mm, still more preferably 10 to 40 N / 50 mm. be. When the breaking strength is in the above range, it is possible to impart good hand-cutting property that can be broken (cut) relatively easily by hand. If the breaking strength is too high, the hand-cutting property is lowered, and it becomes difficult to cut the fiber sheet with one hand, for example. Further, if the breaking strength is too small, the strength of the fiber sheet is insufficient and the fiber sheet is easily broken, resulting in deterioration of durability and handleability. The breaking strength is measured by a tensile test according to JIS L 1913 "General Nonwoven Fabric Test Method".

At least one direction in the sheet surface is a tensile direction when the fiber sheet is cut by hand, and is preferably the second direction. This second direction can be the MD direction, and when the fiber sheet has a length direction and a width direction such as a bandage, it is preferably the length direction of the fiber sheet. That is, when the fiber sheet is used as a bandage, the bandage is usually stretched along the length direction, wound around the application site, and then broken in the length direction. Therefore, the second direction is the tensile direction. It is preferable that the length direction is.

The breaking strength in a direction other than at least one direction in the sheet surface, for example, the first direction (CD direction, etc.) or in the width direction when the fiber sheet has a length direction and a width direction like a bandage, is, for example, 0. It is 1 to 300 N / 50 mm, preferably 0.5 to 100 N / 50 mm, and more preferably 1 to 20 N / 50 mm.

From the viewpoint of hand-cutting property, the fiber sheet is preferably made of only a non-elastomer material, and more specifically, it is preferably made of only fibers. When a layer made of an elastomer or the like is formed on the surface of the fiber sheet, the hand-cutting property may be reduced.

The fiber sheet has a breaking elongation in at least one direction in the sheet surface, for example, 50% or more, preferably 60% or more, and more preferably 80% or more. It is advantageous that the elongation at break is in the above range in order to increase the elasticity of the fiber sheet. The elongation at break in at least one direction in the sheet surface is usually 300% or less, preferably 250% or less. The elongation at break is also measured by a tensile test according to JIS L 1913 "General Nonwoven Fabric Test Method".

At least one direction in the seat surface is preferably the first direction from the viewpoint of ease of bending of the portion when the joint portion or the like is wound around the portion to be bent and stretched. This first direction can be the CD direction, and when the fiber sheet has a length direction and a width direction such as a bandage, it is preferably the width direction of the fiber sheet.

The breaking elongation in a direction other than at least one direction in the sheet surface, for example, a second direction (MD direction or the like), or in the length direction when the fiber sheet has a length direction and a width direction like a bandage, is, for example. It is 10 to 500%, preferably 100 to 350%.

The fiber sheet has a recovery rate after 50% elongation (recovery rate after 50% elongation) in at least one direction in the sheet surface, preferably 70% or more (100% or less), more preferably 80% or more, still more preferable. Is 90% or more. When the 50% elongation recovery rate is in this range, the followability to elongation is improved, and for example, when wound around a joint portion or the like where bending and stretching are performed, the bending motion and shape of the portion are sufficiently followed and the shape is sufficiently followed. It is advantageous for improving the self-adhesiveness due to the friction between the stacked fiber sheets. When the elongation recovery rate is excessively small, the bending operation of the above-mentioned portion cannot be followed, the deformation of the fiber sheet caused by this operation cannot be restored, and the fixing of the wound fiber sheet becomes weak.

At least one direction in the seat surface is preferably the first direction, which is particularly required to follow the bending motion of the joint portion or the like when the portion is wound around the bending and stretching portion. This first direction can be the CD direction, and when the fiber sheet has a length direction and a width direction such as a bandage, it is preferably the width direction of the fiber sheet.

The recovery rate after elongation of 50% is the residual strain (%) after the test when the load is removed immediately after the elongation rate reaches 50% in the tensile test based on JIS L 1913 "General non-woven fabric test method". When is X, the following formula:
Recovery rate after 50% elongation (%) = 100-X
Defined in.

50% post-elongation recovery rate in directions other than at least one direction in the sheet surface, for example, in the second direction (MD direction, etc.) and in the length direction when the fiber sheet has a length direction and a width direction like a bandage. Is, for example, 70% or more (100% or less), preferably 80% or more.

The fiber sheet preferably has a compressive elastic modulus Pe of 85% or less, and more preferably 80% or less. The fact that the compressive elastic modulus Pe is in this range is advantageous in satisfying the above formula [A], and is advantageous in realizing a fiber sheet that does not easily hinder the bending operation of joints and the like. The lower limit of the compressive elastic modulus Pe is not particularly limited, and is, for example, 50%. The compressive elastic modulus Pe is based on JIS L 1913 "general nonwoven fabric test method" and has the following formula [C] :.
Pe = {(T 1'-T) / (T _{1 -} T)} x 100 [C]
It is calculated from. T ₁ is the thickness [mm] when the initial load (0.5 kPa) is applied, and is synonymous with T ₁ in the above formula [A]. T is the thickness [mm] when a load of 30 kPa is applied. T _1'is the thickness [mm] when the initial load is returned.

The basis weight of the fiber sheet is preferably 30 to 300 g / m ² , and more preferably 50 to 200 g / m ² . From the viewpoint of more effectively suppressing the inhibition of bending operation, the basis weight is more preferably 180 g / m ² or less. According to the fiber sheet according to the present invention, when the basis weight is large (for example, 50 g / m ² or more, 70 g / m ² or more, 90 g / m ² or more, 110 g / m ² or more, and further 130 g / m ² or more). Even if there is, it is possible to effectively suppress the inhibition of the bending motion of the joint portion and the like.

The thickness T ₁ of the fiber sheet (this thickness T ₁ is synonymous with T ₁ in the above formula [A]) is, for example, 0.2 to 5 mm, preferably 0.3 to 3 mm, and more preferably. It is 0.4 to 2 mm. When the basis weight and the thickness are in this range, the balance between the bendability when the fiber sheet is wound, the extensibility, the flexibility, the texture and the cushioning property becomes good. The density (bulk density) of the fiber sheet can be a value according to the above-mentioned texture and thickness, for example, 0.03 to 0.5 g / cm ³ , preferably 0.04 to 0.4 g / cm ³ , and more. It is preferably 0.05 to 0.2 g / cm ³ . From the viewpoint of more effectively suppressing the inhibition of the bending operation, the density is more preferably 0.15 g / cm ³ or less.

The fiber sheet preferably has a difference ΔT between the thickness T ₁ when an initial load (0.5 kPa) is applied and the thickness T when a load of 30 kPa is applied, preferably 0.1 mm or more. Is more preferable. The fact that the thickness difference ΔT is in the above range is advantageous in satisfying the above formula [A], and is advantageous in realizing a fiber sheet that does not easily hinder the bending operation of joints and the like. The thickness difference ΔT corresponds to (T ₁ −T) in the above formula [C]. The upper limit of the thickness difference ΔT is not particularly limited, and is, for example, 0.8 mm.

The air permeability of the fiber sheet by the Frazier method is preferably 0.1 cm ³ / (cm ² · sec) or more, more preferably 1 to 500 cm ³ / (cm ² · sec), and further preferably 5 to 300 cm ³ / (. cm ² · sec), particularly preferably 10 to 200 cm ³ / (cm ² · sec). When the degree of air permeability is within this range, the air permeability is good and it is difficult to get wet, so that it is more suitable for applications such as bandages used on the human body.

(2) Composition and Manufacturing Method of Fiber Sheet The fiber sheet is not particularly limited as long as it is composed of fibers, and may be, for example, a woven fabric, a non-woven fabric, a knit (knitted fabric), or the like. The shape of the fiber sheet can be selected according to the intended use, but is preferably a rectangular sheet having a length direction and a width direction such as a tape shape or a strip shape (long shape). The fiber sheet may have a single-layer structure or a multi-layer structure composed of two or more fiber layers.

As a means for imparting elasticity and extensibility to the fiber sheet, 1) a method of gathering a fiber sheet base material such as a woven fabric, a non-woven fabric, and a knit, and 2) an elastic material such as an elastomer typified by rubber. A method of weaving threads into a fiber sheet, 3) a method of combining a layer made of a stretchable material such as an elastomer with a non-stretchable fiber sheet base material, or a method of impregnating a stretchable material, and 4) a method of impregnating a non-woven fabric. Examples thereof include a method of using crimped fibers that are crimped into a coil at least in part.

Among the above, the fiber sheet according to the present invention preferably has the configuration of 4) above. The gather processing of 1) above is effective in that elasticity can be effectively imparted, but it is relatively difficult to obtain a fiber sheet satisfying the above formula [A] due to the wavy shape of the gathers. According to the method of 2) above, the elasticity can be easily imparted, but the woven rubber thread or the like may reduce the bendability when the fiber sheet is wound. As described above, the method of 3) tends to make it relatively difficult to satisfy the above formula [A] by sealing the surface of the fiber sheet with an elastomer.

From the viewpoint of ease of bending of the joint when wrapped around the joint, self-adhesiveness, hand-cutting property, and conformability (fitness) to the uneven part when wrapped around the uneven part such as the joint, the fiber sheet is used. It is preferably composed of a non-woven fabric, that is, a non-woven fabric sheet, more preferably composed of a non-woven fabric containing crimped fibers crimped in a coil shape, and containing the crimped fibers and described in 1) to 3 above. ) Is not further treated with any one or more (preferably all) of the non-woven fabric. Particularly preferably, the non-woven fabric sheet is composed of only the crimped fibers.

In a fiber sheet made of a non-woven fabric containing crimped fibers, the crimped fibers are mainly entangled with each other at their crimped coil portions to be restrained or hooked without substantially fusing each of the constituent fibers. It is preferable to have the above-mentioned structure. Further, it is preferable that most (most) of the crimped fibers (direction of the axis of the crimped fibers) are oriented substantially parallel to the sheet surface. In the specification of the present application, "aligned substantially parallel to the plane direction" means that a large number of crimped fibers (the axial core direction of the crimped fibers) are locally oriented in the thickness direction, for example, entanglement by a needle punch. It means a state in which the portion oriented along the line does not repeatedly exist.

In a fiber sheet composed of a non-woven fabric containing crimped fibers, the crimped fibers are preferably oriented in a certain direction (for example, the above-mentioned second direction, preferably the length direction) in the sheet surface, and are adjacent or adjacent to each other. The intersecting crimp fibers are entangled with each other at their crimp coil portions. Further, even in the thickness direction (or diagonal direction) of the fiber sheet, the crimped fibers are preferably slightly entangled with each other. Entanglement of crimped fibers can occur with the process of shrinking the fiber web, which is the precursor of the fiber sheet.

The non-woven fabric in which the crimped fibers (the axial core direction of the crimped fibers) are oriented in a certain direction in the sheet surface and are entangled with each other exhibits good elasticity (including extensibility) in this direction. When the above-mentioned direction is, for example, the length direction, this stretchable nonwoven fabric has a length because when tension is applied in the length direction, the entangled crimp coil portion expands and tries to return to the original coil shape. It can show high elasticity in the direction. This stretchable nonwoven fabric can exhibit excellent extensibility in a direction orthogonal to a certain direction (for example, a width direction) in the sheet surface. In addition, the light entanglement of the crimped fibers in the thickness direction of the nonwoven fabric can exhibit cushioning properties and flexibility in the thickness direction, whereby the nonwoven fabric can have a good feel and texture. Further, the crimp coil portion is easily entangled with another crimp coil portion by contact with a certain pressure. The self-adhesiveness can be expressed by the entanglement of the crimp coil portion.

In a fiber sheet composed of a non-woven fabric containing crimped fibers, when tension is applied in the orientation direction of the crimped fibers (for example, the above-mentioned second direction, preferably the length direction), the entangled crimped coil portion is elastically deformed. When it is stretched and further tensioned, it finally melts, so that it has good cutability (hand-cutting property).

As described above, the nonwoven fabric that can form the fiber sheet preferably contains crimped fibers that are crimped into a coil shape. The crimped fibers are preferably oriented mainly in the plane direction of the nonwoven fabric, and are preferably crimped substantially uniformly in the thickness direction. The crimped fiber can be composed of a composite fiber in which a plurality of resins having different heat shrinkage rates (or thermal expansion rates) form a phase structure.

The composite fiber constituting the crimped fiber is a fiber (latent winding) having an asymmetrical or layered (so-called bimetal) structure that causes crimping by heating due to the difference in the heat shrinkage rate (or thermal expansion rate) of a plurality of resins. Fribred fiber). Multiple resins usually differ in softening point or melting point. The plurality of resins may be, for example, a polyolefin resin (low density, medium density or high density polyethylene, a poly C _2-4 olefin resin such as polypropylene, etc.); an acrylic resin (acrylonitrile-vinyl chloride copolymer, etc.). Acrylonitrile-based resin having an acrylonitrile unit, etc.); Polypolyacetal-based resin (polyvinyl-acetal resin, etc.); Polyvinyl chloride-based resin (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylonitrile copolymer, etc.); Polyvinylidene chloride resin (vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl acetate copolymer, etc.); styrene resin (heat resistant polystyrene, etc.); polyester resin (polyethylene terephthalate resin, polytrimethylene terephthalate resin, poly) Butylene terephthalate resin, poly-C _2-4 alkylene allylate resin such as polyethylene naphthalate resin, etc.); Polyamide resin (polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc.) Aromatic polyamide resin, semi-aromatic polyamide resin, polyphenylene isophthalamide, polyhexamethylene terephthalamide, poly p-phenylene terephthalamide, etc.); Polyamide resin (bisphenol A type polycarbonate, etc.); Polypara It can be selected from thermoplastic resins such as phenylene benzobisoxazole resin; polyphenylene sulfide resin; polyurethane resin; cellulose resin (cellulose ester and the like). Further, each of these thermoplastic resins may contain other copolymerizable units.

Among them, the above-mentioned plurality of resins are non-wet and heat adhesive resins (or heat-resistant hydrophobic resins) having a softening point or a melting point of 100 ° C. or higher because they are melted or softened even when heat-treated with high-temperature steam and the fibers are not fused. Alternatively, non-aqueous resin), for example, polypropylene-based resin, polyester-based resin, and polyamide-based resin are preferable, and aromatic polyester-based resin and polyamide-based resin are particularly preferable from the viewpoint of excellent balance of heat resistance and fiber-forming property. It is preferable that at least the resin exposed on the surface of the composite fiber is a non-moist heat adhesive fiber so that the composite fiber (latent crimp fiber) constituting the non-woven fabric is not fused even if the composite fiber (latent crimp fiber) is treated with high temperature steam.

The plurality of resins constituting the composite fiber may have different heat shrinkage rates, and may be a combination of resins of the same type or a combination of different resins.

From the viewpoint of adhesion, it is preferable that the plurality of resins constituting the composite fiber are a combination of resins of the same type. In the case of a combination of resins of the same type, a combination of a component (A) forming a homopolymer (essential component) and a component (B) forming a modified polymer (copolymer) is usually used. That is, it is more crystallized than the homopolymer by modifying the homopolymer, which is an essential component, by copolymerizing, for example, a copolymerizable monomer that lowers the crystallinity, melting point, softening point, etc. The degree may be lowered or made amorphous, and the melting point, softening point, etc. may be lowered as compared with the copolymer. By changing the crystallinity, melting point or softening point in this way, it is possible to make a difference in the heat shrinkage rate. The difference in melting point or softening point can be, for example, 5 to 150 ° C, preferably 40 to 130 ° C, and more preferably 60 to 120 ° C. The proportion of the copolymerizable monomer used for the modification is, for example, 1 to 50 mol%, preferably 2 to 40 mol%, more preferably 3 to 30 mol% (particularly 5 to 5 to 5 to 30 mol%) with respect to all the monomers. 20 mol%). The mass ratio of the component forming the homopolymer and the component forming the modified polymer can be selected according to the structure of the fiber. For example, the homopolymer component (A) / the modified polymer component (B) =. It is 90/10 to 10/90, preferably 70/30 to 30/70, and more preferably 60/40 to 40/60.

Since it is easy to produce a latent crimpable composite fiber, the composite fiber is a combination of an aromatic polyester resin, particularly a combination of a polyalkylene allylate resin (a) and a modified polyalkylene allylate resin (b). It is preferable to have. The polyalkylene allylate resin (a) contains an aromatic dicarboxylic acid (terephthalic acid, a symmetric aromatic dicarboxylic acid such as naphthalen-2,6-dicarboxylic acid, etc.) and an alkanediol component (such as ethylene glycol and butylene glycol). It can be a homopolymer with C _2-6 alkanediol or the like). Specifically, a poly C _2-4 alkylene terephthalate resin such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) is used, and a general PET having an intrinsic viscosity of 0.6 to 0.7 is usually used. PET used for fibers is used.

On the other hand, in the modified polyalkylene allylate-based resin (b), as a copolymerization component that lowers the melting point or softening point and the degree of crystallization of the polyalkylene allylate-based resin (a), which is an essential component, for example, an asymmetric aromatic dicarboxylic acid. Examples thereof include a dicarboxylic acid component such as an acid, an alicyclic dicarboxylic acid, and an aliphatic dicarboxylic acid, an alkanediol component having a longer chain length than the alkanediol of the polyalkylene allylate resin (a), and / or an ether bond-containing diol component. Will be. The copolymerization component can be used alone or in combination of two or more. Among these components, the dicarboxylic acid components include asymmetric aromatic dicarboxylic acids (isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, etc.) and aliphatic dicarboxylic acids (C _6-12 aliphatic dicarboxylic acids such as adipic acid). Acid) and the like are widely used, and as diol components, alcandiol (1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, C _3-6 alcandiol such as neopentylglycol, etc.), etc. Polyoxyalkylene glycol (diethylene glycol, triethylene glycol, polyethylene glycol, polyoxy C _2-4 alkylene glycol such as polytetramethylene glycol, etc.) and the like are widely used. Of these, asymmetric aromatic dicarboxylic acids such as isophthalic acid, polyoxy C _2-4 alkylene glycols such as diethylene glycol, and the like are preferable. Further, the modified polyalkylene allylate resin (b) may be an elastomer having C _2-4 alkylene arylate (ethylene terephthalate, butylene terephthalate, etc.) as a hard segment and (poly) oxyalkylene glycol or the like as a soft segment. ..

In the modified polyalkylene allylate-based resin (b), the ratio of the dicarboxylic acid component (for example, isophthalic acid) for lowering the melting point or the softening point is the ratio of the dicarboxylic acid component constituting the modified polyalkylene allylate-based resin (b). It is, for example, 1 to 50 mol%, preferably 5 to 50 mol%, and more preferably 15 to 40 mol% with respect to the total amount. Further, the ratio of the diol component (for example, diethylene glycol or the like) for lowering the melting point or the softening point is, for example, 30 mol% or less with respect to the total amount of the diol component constituting the modified polyalkylene allylate resin (b). It is preferably 10 mol% or less (for example, 0.1 to 10 mol%). If the proportion of the copolymerization component is too low, sufficient crimping does not occur, and the morphological stability and elasticity of the nonwoven fabric after the crimping develops deteriorate. On the other hand, if the proportion of the copolymerization component is too high, the crimp expression performance is high, but it becomes difficult to spin stably.

The modified polyalkylene allylate resin (b) may be a polyvalent carboxylic acid component such as trimellitic acid or pyromellitic acid, a polyol component such as glycerin, trimethylolpropane, trimethylolethane, or pentaerythritol, if necessary. May be contained as a monomer component.

The cross-sectional shape of the composite fiber (cross-sectional shape perpendicular to the longitudinal direction of the fiber) is a round cross-section or atypical cross-section [flat, elliptical, polygonal, 3-14 leaf-shaped, T, which is a general solid cross-sectional shape. It is not limited to [shaped, H-shaped, V-shaped, dogbone (I-shaped), etc.], and may have a hollow cross section, etc., but usually has a round cross section.

The cross-sectional structure of the composite fiber includes a phase structure formed by a plurality of resins, for example, a core sheath type, a sea island type, a blend type, a parallel type (side-by-side type or multi-layer bonding type), and a radial type (radial bonding type). ), Hollow radiation type, block type, random composite type and other structures can be mentioned. Of these, a structure in which the phase portions are adjacent to each other (so-called bimetal structure) or a structure in which the phase structure is asymmetric, for example, an eccentric core sheath type or a parallel type structure is preferable because spontaneous crimping is likely to occur by heating.

When the composite fiber has a core-sheath type structure such as an eccentric core-sheath type, the core portion has a heat shrinkage difference from the non-moisture-heat adhesive resin of the sheath portion located on the surface and can be crimped. Is a wet heat adhesive resin (for example, ethylene-vinyl alcohol copolymer, vinyl alcohol polymer such as polyvinyl alcohol, etc.) and a thermoplastic resin having a low melting point or softening point (for example, polystyrene, low density polyethylene, etc.). It may be composed of.

The average fineness of the composite fiber is, for example, 0.1 to 50 dtex, preferably 0.5 to 10 dtex, and more preferably 1 to 5 dtex. If the fineness is too small, it is difficult to manufacture the fiber itself and it is difficult to secure the fiber strength. In addition, in the process of developing crimps, it becomes difficult to develop beautiful coiled crimps. On the other hand, if the fineness is too high, the fibers become rigid and it becomes difficult to develop sufficient crimping.

The average fiber length of the composite fiber is, for example, 10 to 100 mm, preferably 20 to 80 mm, and more preferably 25 to 75 mm. If the average fiber length is too short, it becomes difficult to form a fiber web, and when crimping is developed, the entanglement between the crimped fibers becomes insufficient, and it may be difficult to secure the strength and elasticity of the nonwoven fabric. .. If the average fiber length is too long, it becomes difficult to form a fiber web with a uniform basis weight, and at the time of web formation, many fibers are entangled with each other, and when crimping is developed, they interfere with each other and expand and contract. Sexual expression can be difficult. When the average fiber length is within the above range, a part of the fibers crimped on the surface of the nonwoven fabric is appropriately exposed on the surface of the nonwoven fabric, so that the self-adhesiveness of the nonwoven fabric can be improved. Further, the average fiber length in the above range is also advantageous for obtaining good hand-cutting property.

The composite fiber is a latent crimped fiber, and when heat-treated, the crimp is developed (or manifested), and becomes a fiber having a substantially coil-like (spiral or spiral spring-like) three-dimensional crimp.

The number of crimps (mechanical crimps) before heating is, for example, 0 to 30 pieces / 25 mm, preferably 1 to 25 pieces / 25 mm, and more preferably 5 to 20 pieces / 25 mm. The number of crimps after heating is, for example, 30 pieces / 25 mm or more (for example, 30 to 200 pieces / 25 mm), preferably 35 to 150 pieces / 25 mm.

As described above, the crimped fibers constituting the non-woven fabric have substantially coiled crimps after the onset of crimps. The average radius of curvature of the circle formed by the coil of the crimped fiber is, for example, 10 to 250 μm, preferably 20 to 200 μm, and more preferably 50 to 160 μm. The average radius of curvature is an index showing the average size of the circle formed by the coils of the crimped fibers. When this value is large, the formed coil has a loose shape, in other words, the number of crimps. It means that it has a small shape. Further, when the number of crimps is small, the entanglement between the crimp fibers is also small, and it becomes difficult to recover the shape due to the deformation of the coil shape, which is disadvantageous for exhibiting sufficient expansion / contraction performance. If the average radius of curvature is too small, the crimped fibers are not sufficiently entangled with each other, making it difficult to secure the web strength, and the stress when the shape of the coil is deformed is too large to cause the breaking strength to be excessively large. Therefore, it becomes difficult to obtain appropriate elasticity.

In the crimped fiber, the average pitch (average crimping pitch) of the coil is, for example, 0.03 to 0.5 mm, preferably 0.03 to 0.3 mm, and more preferably 0.05 to 0.2 mm. .. If the average pitch is excessively large, the number of coil crimps that can be developed per fiber is reduced, and sufficient elasticity cannot be exhibited. If the average pitch is excessively small, the crimped fibers are not sufficiently entangled with each other, and it becomes difficult to secure the strength of the nonwoven fabric.

The non-woven fabric (fiber web) may contain other fibers (non-composite fibers) in addition to the above-mentioned composite fibers. Specific examples of non-composite fibers include fibers composed of the above-mentioned non-wet heat-adhesive resin or moist heat-adhesive resin, cellulose-based fibers [for example, natural fibers (cotton, wool, silk, linen, etc.), and semi-synthetic fibers. It includes fibers composed of fibers (acetate fibers such as triacetate fibers), regenerated fibers (rayon, polynosic, cupra, lyocell (for example, registered trademark name: "Tencel" etc.))] and the like. The average fineness and average fiber length of the non-composite fibers can be similar to those of the composite fibers. Non-composite fibers can be used alone or in combination of two or more.

It is preferable that the ratio (mass ratio) of the composite fiber and the non-composite fiber is appropriately adjusted so that the fiber sheet satisfies the above formula [A]. The ratio is, for example, composite fiber / non-composite fiber = 50/50 to 100/0, preferably 60/40 to 100/0, more preferably 70/30 to 100/0, and even more preferably 80/20 to. It is 100/0, particularly preferably 90/10 to 100/0. By blending non-composite fibers, the balance between the strength of the nonwoven fabric and its elasticity or flexibility can be adjusted.

Non-woven fabrics (fiber webs) are conventional additives such as stabilizers (heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, etc.), antibacterial agents, deodorants, fragrances, colorants (dye pigments, etc.). ), Filler, antistatic agent, flame retardant, plasticizer, lubricant, crystallization rate retarder and the like. Additives can be used alone or in combination of two or more. The additive may be supported on the surface of the fiber or may be contained in the fiber.

The fiber sheet composed of the non-woven fabric containing the crimped fiber has a step of web-forming the fiber containing the composite fiber (latent crimped fiber) (web-making step) and a step of heating the fiber web to crimp the composite fiber. It can be suitably produced by a method including a step (heating step).

As a method for forming a fiber web in the web forming process, a conventional method, for example, a direct method such as a spunbond method and a melt blow method, a card method using a melt blow fiber or a staple fiber, a dry method such as an air array method, etc. Can be used. Among them, the card method using melt blow fiber and staple fiber, particularly the card method using staple fiber is widely used. Examples of the web obtained by using the staple fiber include a random web, a semi-random web, a parallel web, a cross wrap web, and the like.

Prior to the heating step, an entanglement step of entwining at least a part of the fibers in the fiber web may be performed. By carrying out this entanglement step, a non-woven fabric in which the crimped fibers are appropriately entangled can be obtained in the next heating step. The entanglement method may be a method of mechanically entwining, but a method of entanglement by spraying or spraying (spraying) water is preferable. Entangling the fibers with a stream of water is advantageous in increasing the density of entanglement due to crimping in the heating process. The water to be sprayed or sprayed may be sprayed from one side of the fiber web or from both sides, but it is preferable to spray from both sides from the viewpoint of efficiently performing strong entanglement.

The water ejection pressure in the entanglement step is, for example, 2 MPa or more, preferably 3 to 12 MPa, and more preferably 4 to 10 MPa so that the fiber entanglement is in an appropriate range. The temperature of the sprayed or jetted water is, for example, 5 to 50 ° C, preferably 10 to 40 ° C.

As a method of spraying or spraying water, a method of spraying water using a nozzle or the like having a regular spray area or a spray pattern is preferable from the viewpoint of convenience and the like. Specifically, water can be sprayed on the fiber web transferred by a belt conveyor such as an endless conveyor while being placed on the conveyor belt. The conveyor belt may be water-permeable, or water may be sprayed onto the fiber web by passing the water-permeable conveyor belt from the back side of the fiber web. The fiber web may be wetted with a small amount of water in advance in order to suppress the scattering of the fibers due to the spraying of water.

As the nozzle for spraying or spraying water, a plate or die in which predetermined orifices are continuously arranged in the width direction may be used, and the orifices may be arranged so as to be arranged in the width direction of the fiber web to which the predetermined orifices are continuously arranged. The orifice row may be one or more rows, and a plurality of rows may be arranged in parallel. Further, a plurality of nozzle dies having one row of orifice rows may be installed in parallel.

Prior to the above-mentioned entanglement step, a step (uneven distribution step) may be provided in which the fibers in the fiber web are unevenly distributed in the plane. By carrying out this step, a region where the fiber density becomes sparse is formed in the fiber web, so that when the entanglement step is water flow entanglement, the water flow is efficiently jetted into the inside of the fiber web. This makes it easier to achieve appropriate entanglement not only on the surface of the fiber web but also on the inside.

The uneven distribution step can be performed by spraying or spraying low pressure water onto the fiber web. The spraying or spraying of low pressure water onto the fiber web may be continuous, but is preferably intermittent or periodic. By intermittently or periodically spraying water on the fiber web, a plurality of low density portions and a plurality of high density portions can be formed periodically and alternately.

The water ejection pressure in the uneven distribution step is preferably as low as possible, for example, 0.1 to 1.5 MPa, preferably 0.3 to 1.2 MPa, and more preferably 0.6 to 1.0 MPa. The temperature of the sprayed or jetted water is, for example, 5 to 50 ° C, preferably 10 to 40 ° C.

The method of intermittently or periodically spraying or spraying water is not particularly limited as long as it can periodically and alternately form a density gradient on the fiber web, but from the viewpoint of convenience and the like, a plurality of holes are used. A method of spraying water through a formed regular spray area or a plate-like material having a spray pattern (perforated plate or the like) is preferable.

In the heating step, the fiber web is heated with high temperature steam and crimped. In the method of treating with high temperature steam, the fiber web is exposed to a high temperature or superheated steam (high pressure steam) flow, which causes coil crimping of the composite fiber (latent crimped fiber). Since the fiber web has breathability, high-temperature steam permeates into the inside even when treated from one direction, and substantially uniform crimping occurs in the thickness direction, and the fibers are uniformly entangled with each other. ..

The fiber web shrinks at the same time as the high temperature steam treatment. Therefore, it is desirable that the fiber web to be supplied is overfed according to the area shrinkage rate of the target nonwoven fabric immediately before being exposed to high temperature steam. The ratio of overfeed is 110 to 300%, preferably 120 to 250%, based on the length of the target nonwoven fabric.

A conventional steam injection device can be used to supply steam to the fiber web. The steam injection device is preferably a device capable of spraying steam substantially uniformly over the entire width of the fiber web at a desired pressure and amount. The steam injection device may be provided only on one surface side of the fiber web, or may be further provided on the other surface side in order to steam treat the front and back surfaces of the fiber web at the same time.

Since the high-temperature steam injected from the steam injection device is an air flow, it enters the inside of the fiber web without significantly moving the fibers in the fiber web, unlike the water flow entanglement treatment and the needle punching treatment. Due to the ingress of the water vapor flow into the fiber web, the water vapor flow efficiently covers the surface of each fiber existing in the fiber web, enabling uniform thermal crimping. Further, as compared with the dry heat treatment, since heat can be sufficiently conducted to the inside of the fiber web, the degree of crimping in the surface direction and the thickness direction becomes almost uniform.

Similar to the above-mentioned water flow entanglement nozzle, the nozzle for injecting high-temperature steam also uses a plate or die in which predetermined orifices are continuously arranged in the width direction, and the orifice in the width direction of the fiber web to which this is supplied. It should be arranged so that they are lined up. The orifice row may be one or more rows, and a plurality of rows may be arranged in parallel. Further, a plurality of nozzle dies having one row of orifice rows may be installed in parallel.

The pressure of the high temperature steam to be used can be selected from the range of 0.1 to 2 MPa (for example, 0.2 to 1.5 MPa). If the pressure of the water vapor is too high, the fibers forming the fiber web may move more than necessary to cause turbulence in the formation, or the fibers may be entangled more than necessary. If the pressure is too weak, the amount of heat required to develop the crimp of the fiber cannot be applied to the fiber web, or water vapor cannot penetrate the fiber web, and the development of the crimp of the fiber in the thickness direction becomes non-uniform. It's easy to do. The temperature of the high-temperature steam can be selected from the range of 70 to 180 ° C. (for example, 80 to 150 ° C.), although it depends on the material of the fiber and the like. The treatment rate of high-temperature steam can be selected from the range of 200 m / min or less (for example, 0.1 to 100 m / min).

After the crimping of the composite fiber in the fiber web is developed in this way, moisture may remain on the non-woven fabric. Therefore, a drying step of drying the non-woven fabric may be provided if necessary. As a drying method, a method using a drying facility such as a cylinder dryer or a tenter; a non-contact method such as far-infrared irradiation, microwave irradiation, electron beam irradiation; a method of blowing hot air or passing through hot air, etc. Can be mentioned.

In the method for producing a fiber sheet as described above, as a method for satisfying the above formula [A], for example, a method for adjusting the content ratio of the composite fiber and the non-composite fiber; the condition of high temperature steam used in the heating step ( In particular, a method of adjusting the temperature and / or pressure); a method of adjusting the drying temperature in the drying step and the like can be mentioned.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, each physical property value in the fiber sheet (bandage) obtained in the following Examples and Comparative Examples was measured by the following method.

[1] Number of mechanical crimps (pieces / 25 mm)
The measurement was performed according to JIS L 1015 “Chemical fiber staple test method” (8.12.1).

[2] Average number of coil crimps (pieces / mm)
The crimped fiber (composite fiber) is extracted from the fiber sheet while being careful not to stretch the coil crimped, and JIS L 1015 "Chemical fiber staple test method" (8.12.1) is the same as the measurement of the mechanical crimped number. ) Was measured.

[3] Average crimp pitch (μm)
When measuring the average coil crimp number, the distance between adjacent coils was continuously measured, and the average value of n number = 100 was measured.

[4] Average radius of curvature (μm)
Using a scanning electron microscope (SEM), an arbitrary cross section of the fiber sheet was photographed at a magnification of 100 times. Among the fibers shown in the cross-sectional photograph taken, the radius of the circle (curvature from the coil axis direction) when a circle is drawn along the spiral for the fiber forming a spiral (coil) of one circumference or more. The radius of the circle when observing the fiber) was obtained, and this was defined as the radius of curvature (μm). When the fiber spirals in an elliptical shape, the radius of curvature is ½ of the sum of the major axis and the minor axis of the ellipse. However, in order to exclude the case where the crimped fiber does not exhibit sufficient coil crimping or the case where the spiral shape of the fiber is observed as an ellipse, the major axis and the minor axis of the ellipse are used. Only ellipses whose ratio of were in the range of 0.8 to 1.2 were measured. The average radius of curvature (μm) was determined as the average value of n number = 100.

[5] Metsuke (g / m ² )
The measurement was performed according to JIS L 1913 "General non-woven fabric test method".

[6] Thickness (mm)
The thickness T ₁ of one sheet was measured according to the method A (load: 0.5 kPa) of JIS L 1913. Further, under the same conditions, T ₃ was measured as the thickness when three sheets were stacked. From these measured values, {T ₃ / (3 × T ₁ )} × 100, which is the left side of the above equation [A], was calculated.

[7] Density (g / cm ³ )
The density was calculated from the basis weight measured by the method of [5] and the thickness T ₁ measured by the method of [6].

[8] Breaking strength (N / 50 mm) and breaking elongation (%)
The measurement was performed according to JIS L 1913 "General non-woven fabric test method". Measurements were made in each of the length direction (MD direction) and the width direction (CD direction) of the fiber sheet.

[9] 50% elongation stress (N / 50 mm)
The measurement was performed according to JIS L 1913 "General non-woven fabric test method". Let S ₁ be the stress at 50% elongation in the width direction (first direction, CD direction) of the fiber sheet, and S ₂ be the stress at 50% elongation in the length direction (second direction, MD direction).

[10] Recovery rate after 50% elongation A tensile test was carried out in accordance with JIS L 1913 "General non-woven fabric test method", and the following formula:
Recovery rate after 50% elongation (%) = 100-X
The recovery rate after 50% elongation was determined based on the above. In the formula, X is the residual strain (%) after the test when the load is removed immediately after the elongation reaches 50% in the tensile test. The recovery rate after 50% elongation was measured in each of the length direction (MD direction) and the width direction (CD direction) of the fiber sheet.

[11] Compressive modulus Pe (%)
Calculated based on the above formula [C] in accordance with JIS L 1913 "General non-woven fabric test method".

[12] Thickness difference ΔT (mm)
The thickness difference ΔT was obtained as (T ₁ −T) in the above formula [C].

[13] Curved surface slip stress (N / 50 mm)
First, the fiber sheet was cut into a size of 50 mm width × 600 mm length so that the MD direction was the length direction, and used as sample 1. Next, as shown in FIG. 1A, after fixing one end of the sample 1 to the winding core 3 (polypropylene resin pipe roll having an outer diameter of 30 mm × length of 150 mm) with a single-sided adhesive tape 2, this is performed. Using an alligator clip 4 (grasping width 50 mm, 0.5 mm thick rubber sheet fixed to the inside of the mouth with double-sided tape) at the other end of sample 1 is uniform with respect to the entire width of sample 1. A weight 5 of 150 g was attached so as to be weighted.

Next, with the winding core 3 to which the sample 1 is fixed is lifted so that the sample 1 and the weight 5 are suspended, the winding core 3 is rotated 5 times so that the weight 5 does not shake significantly, and the sample 1 is wound up and the weight is wound. 5 was lifted (see FIG. 1 (b)). In this state, the contact point between the columnar portion in the outermost peripheral portion of the sample 1 wound around the core 3 and the planar portion of the sample 1 not wound around the core 3 (the portion of the sample 1 wound around the core 3). And the boundary line with the part of the sample 1 that is vertical due to the gravity of the weight 5) is set as the base point 6, and the alligator clip 4 and the weight 5 are slowly moved so that the base point 6 does not move and shift. I removed it. Next, at a point 7 that is half a circumference (180 °) along the sample 1 wound around the core 3 from this base point 6, the outermost peripheral portion of the sample 1 is cut with a razor blade so as not to damage the sample in the inner layer. A cut 8 was provided (see FIG. 2).

The curved surface slip stress between the outermost layer portion in this sample 1 and the inner layer portion wound around the core 3 below it (inner layer) was measured. A tensile tester (“Autograph” manufactured by Shimadzu Corporation) was used for this measurement. The winding core 3 is fixed to the jig 9 installed on the fixed side chuck pedestal of the tensile tester (see FIG. 3), and the end portion of the sample 1 (the end portion to which the alligator clip 4 is attached) is attached to the chuck 10 on the load cell side. The measured value (tensile strength) when the sample 1 was detached (separated) at the cut 8 was defined as the curved surface slip stress.

1. 1. Preparation of fiber sheet <Example 1>
As latent crimp fibers, a polyethylene terephthalate resin having an intrinsic viscosity of 0.65 [component (A)] and a modified polyethylene terephthalate resin [component (B)] obtained by copolymerizing 20 mol% of isophthalic acid and 5 mol% of diethylene glycol are used. Constructed side-by-side composite staple fiber ["Sofit PN780" manufactured by Kuraray Co., Ltd., 1.7 dtex x 51 mm length, mechanical crimp number 12/25 mm, 130 ° C x 1 minute crimp number 62 after heat treatment / 25 mm] was prepared. Using 100% by mass of this side-by-side type composite staple fiber, a card web having a basis weight of 30 g / m ² was obtained by the card method.

This card web is moved on a conveyor net, passed between a perforated plate drum having staggered holes (circular shape) with a diameter of 2 mmφ and a pitch of 2 mm, and headed toward the web and the conveyor net from the inside of the perforated plate drum. Then, a water flow was sprayed at 0.8 MPa in the form of a spray to carry out an uneven distribution step of periodically forming a low-density region and a high-density region of the fiber.

Next, the card web was transferred to the heating step while overfeeding the web to about 200% so as not to inhibit the shrinkage in the heating step due to the next steam.

Next, the card web was introduced into the steam injection device provided on the belt conveyor, and steam at 0.5 MPa and a temperature of about 160 ° C. was ejected perpendicularly to the card web from this steam injection device to perform steam treatment, and latent winding was performed. The coiled crimps of the crimped fibers were expressed and the fibers were entangled. In this steam injection device, a nozzle was installed in one of the conveyors so as to blow steam toward the card web through a conveyor belt. The hole diameter of the steam injection nozzle was 0.3 mm, and a device in which the nozzles were arranged in a row at a pitch of 2 mm along the conveyor width direction was used. The processing speed was 8.5 m / min, and the distance between the nozzle and the conveyor belt on the suction side was 7.5 mm. Finally, it was dried with hot air at 120 ° C. for 1 minute to obtain an elastic fiber sheet.

When the surface of the obtained fiber sheet and the cross section in the thickness direction were observed with an electron microscope (100 times), each fiber was oriented substantially parallel to the surface direction of the fiber sheet and crimped substantially uniformly in the thickness direction. Was.

<Example 2>
An elastic fiber sheet was produced in the same manner as in Example 1 except that the temperature for hot air drying was 140 ° C. When the surface of the obtained fiber sheet and the cross section in the thickness direction were observed with an electron microscope (100 times), each fiber was oriented substantially parallel to the surface direction of the fiber sheet and crimped substantially uniformly in the thickness direction. Was. The basis weight of the card web used in Example 1, Example 2 and Comparative Example 1 described later is the same (30 g / m ² ).

<Comparative Example 1>
An elastic fiber sheet was produced in the same manner as in Example 1 except that the temperature for hot air drying was 160 ° C. When the surface of the obtained fiber sheet and the cross section in the thickness direction were observed with an electron microscope (100 times), each fiber was oriented substantially parallel to the surface direction of the fiber sheet and crimped substantially uniformly in the thickness direction. Was.

<Comparative Example 2>
As the fibers constituting the card web, 80% by mass of the latent crimpable fiber used in Example 1 and 20% by mass of the heat-sealing fiber (“Sofista S220” manufactured by Kuraray Co., Ltd., 3.3 dtex × 51 mm length). A card web having a grain size of 30 g / m ² was produced in the same manner as in Example 1 except that the card web was used, and an elastic fiber sheet was prepared in the same manner as in Example 1 except that this card web was used. Made.

<Comparative Example 3>
On one side of a commercially available polyester spunbonded non-woven fabric (“Ecre 3201A” manufactured by Toyobo Co., Ltd.) having a three-layer structure consisting of a spunbond non-woven fiber layer / melt blown non-woven fiber layer / spunbond non-woven fiber layer. , Commercially available polyurethane melt-blown non-woven fabric ("Melt-blown UC0060" manufactured by Kuraray Laflex Co., Ltd.) is heat-embossed at a processing temperature of 130 ° C while stretching 1.5 times, and gathered by relaxing the stretching. To prepare an elastic fiber sheet.

2. 2. Evaluation of fiber sheet The following evaluation test was conducted on the obtained fiber sheet.

(Easiness of bending of joints after wrapping fiber sheet)
A fiber sheet with a width of 5 cm is wound around the second joint of the index finger three times while being stretched by 30%, and the tension and hardness applied to the finger when the second joint is bent are evaluated on the following five grades. The average score of 5 subjects was calculated. In Comparative Examples 1 to 3, especially in Comparative Example 3, when the second joint portion was bent, the fiber sheet was folded into a wrinkle shape (wavy shape) inside the joint portion, and it seemed that it was difficult to bend in appearance.

Score 5: I don't feel any tension or hardness at all.
Score 4: I don't feel much tension or hardness,
Score 3: Feel the tension and hardness a little,
Score 2: Feel the tension and hardness strongly,
Score 1: Feel the tension and hardness extremely strongly.

1 sample, 2 single-sided adhesive tape, 3 winding cores, 4 alligator clips, 5 weights, 6 base points, points half a circle from 7 base points, 8 cuts, 9 jigs, 10 chucks.

Claims (8)

When the thickness of one sheet measured according to the A method of JIS L 1913 is T ₁ [mm] and the thickness of three sheets measured under the same conditions is T ₃ [mm], the following formula is used. :
80 [%] ≤ {T ₃ / (3 x T ₁ )} x 100 ≤ 81.6 [%]
It contains only crimped fibers that are coiled from latent crimped fibers that satisfy the requirements.
A fiber sheet in which the latent crimpable fiber is a composite fiber . The stress during elongation when stretched at a elongation rate of 50% in the first direction in the plane is 50% stress during elongation S ₁ [N / 50 mm], and the elongation rate 50 in the plane in the second direction orthogonal to the first direction. When the stress at extension when extended at% is 50% stress at extension S ₂ [N / 50 mm], the following formula:
S ₂ / S ₁ ≧ 3
The fiber sheet according to claim 1. Has a length direction and a width direction,
The fiber sheet according to claim 2, wherein the first direction is the width direction. The fiber sheet according to any one of claims 1 to 3, which has a basis weight of 50 g / m ² or more. The fiber sheet according to any one of claims 1 to 4, wherein the compressive elastic modulus measured according to JIS L 1913 is 85% or less. The fiber sheet according to any one of claims 1 to 5, wherein the curved surface slip stress is 3 to 30 N / 50 mm. The fiber sheet according to any one of claims 1 to 6, which is a non-woven fabric sheet. The fiber sheet according to any one of claims 1 to 7, which is a bandage.

Images